A thought that would combine runes/ruins with wards/swords/words all-in-one...
A 'rune' is not only an ancient, forgotten language (so it is literally a language fallen into 'ruin'), but significantly it is one associated with secrets, prophecy and magic. A 'rune' is also naturally related to 'ruin' in that a 'rune' is often 'engraved' or 'graven' on graves, stones, and bones, all of which evoke death, the passage of history, and the uniquely human impulse to hold onto something and record something of ourselves for posterity -- arrest time -- in the midst of this inevitable decay to which we feel subject. The 'casting of the runes' is an attempt to harness 'lady luck' in ones favor and/or tell the future. In other words, prophecy is just another way of trying to control time. See Wikipedia entry:
Runes were thought to have magical powers particularly in the sense of 'warding against', or 'warding off' harm-- hence a kind of protective charm or weapon. Again, words as swords! There is a sense that this 'warding' function is particularly critical at Winterfell, e.g. the swords laid over the tombs in the crypts, the stone direwolves standing vigil as if guarding their entombed human counterparts, or even the cryptic words 'there must always be a Stark at Winterfell' (that's another pun for another time...Winterfell, Winter fell, Winter hell, etc...).
From this perspective, it is interesting to revisit the idea of a human 'ward' who in a sense is a human 'sword,' which you've previously raised. Unfortunately I have not read any of your theories regarding Theon (the quintessential ward) aligned with Ice (the quintessential sword), but that is a most intriguing idea which the text could certainly support!
The word 'ward' itself is very revealing, its meaning being equivocal after deconstruction. Considering it first as a verb, from which the noun is derived, 'ward' has the general meaning of to 'protect' or 'safeguard' (as in warden or guardian). Turning to the noun 'ward' with this in mind, we may understand that Theon is under the protection of Lord Stark who is his guardian. From this perspective, it would appear that Ned is protecting Theon (he's given his 'word' to Balon that no harm shall come to Theon, provided Balon does not act up and act out, Balon correspondingly having given his own 'word' not to do anything to compromise the agreement; thus the 'ward' is sealed with the 'word' of both parties).
However, the darker, thinly-veiled, unspoken subtext here is that it's the other way around -- Theon in actual fact is there to protect the Starks! Moreover, should Balon fail in his word, Theon will be executed. This implicit threat is mirrored in the opening scene with the Night's Watch deserter, where the sentence is passed on the one entrusted to guard the realms of men, for going back on his word and failing to do his duty (more on that later). This is a sacred vow, not one to be taken lightly. Since the Greyjoy uprising was quelled, the sacred duty of preserving the realms of men also resides in the aptly-named Theon (meaning 'godly') who is the ward-- the lucky charm, the amulet, the 'rune' -- Ned has brought back with him to Winterfell as 'protection' (a word often used euphemistically, cf. the Mafia 'protection racket') against Balon Greyjoy's potential future wrath.
Theon is basically a hostage, at whose expense peace has been ransomed. Therefore, Theon is just as important to the Starks' safety as the greatsword Ice, which makes his later betrayal of Winterfell even more egregious. In so far as Theon fails to remain 'true,' thus failing as a 'rune,' he becomes a corrupted 'rune' -- hence a 'ruined' rune! As we have seen, words and names in GRRM's universe are intimately endowed with power, so when Theon ceases being a 'rune,' evolving instead into a 'ruin' of his former self, it is fitting that he loses his godly name 'Theon' and becomes the ruined man, the dehumanized 'Reek,' until such time as Bran, essentially the new Lord and spiritual heart of Winterfell, magically restores his true name (whereupon Theon once more resumes his protector function of the Starks in rescuing and defending Jeyne, whom is assumed by many to be Arya).
Resonating with all these themes, it is noteworthy that the first time we are introduced to Theon, his function is to unsheathe and present Ned's sword for an execution. In the relevant scene we have a congregation of all the elements of 'ward',' sword', and 'word' (as well as 'ruin' and 'rune'). It's noteworthy that the 'word' and the 'sword' are combined as one in the Stark injunction that 'the one who passes the sentence should swing the sword.' Moreover, the sentence is pronounced and passed, because the deserter has not remained true to his word (breaking his Night's Watch vow to remain at his post no matter what may come, until his death). By not remaining true, the deserter has defiled the reputation of the Night's Watch and 'ruined' his honor. Death is the outcome.
This also ties in with the idea that the Wall of ice (like sword 'Ice') itself is a magical ward, and that this magic can only hold so long as the Night's Watch men remain 'true' to their word. 'Spells are locked into' the ice, evoking the 'warding' function of 'words' which are 'runes' inscribed into a stone wall or on a grave, but it goes further than that... The Wall not only contains runes upon it, the runes are essentially 'locked beneath' it, indicating that magic is the foundation guaranteeing its very structural integrity; in other words, which gave rise to and keeps the wall standing in the first place. Taken together with the fact that the wall exists as some form of protection (from whom and for whom, as in the case of Theon as ward, is as yet not completely clear, and may yet still prove equivocal), from a certain point of view then, the Wall is a gigantic Rune!
Melisandre calls the Wall '[her and Jon's] place,' indicating that it is a locus of magic and power, both earthly and otherworldly, a nexus of fire and ice, describing it as a 'hinge' -- implying that if these runes could be deciphered, the wall will swing open giving rise to a door (analogous to Sam passing through the secret gate by saying the 'right' words):
Note too the pun on the word 'grave'...'you may have grave need of me...' (Hmmm... no comment!)
The sword-as-ward/word metaphor is reinforced by Ice's magical elements being 'spell-forged' (a kind of 'rune'), and the fact that the sword is anthropomorphized, as all the Valyrian swords of the Great Houses typically are. Ice is compared to 'a man's hand' and said to be 'taller than Robb' (almost as if the sword were a man standing next to Robb and Theon), a key figure in the action. Moreover, the sword itself 'speaks the sentence' (in that it is used to behead the offender)! GRRM often portrays swords as having voices, e.g. in his frequent descriptions of swords 'singing.' 'Perhaps on account of being transformed by Valyrian 'spells' (runes/words), the Valyrian swords especially become individuals in their own right, each with its unique character reflected in its own special name and corresponding characteristic house 'words.' For example, 'Dark Sister' is a sister sword to 'Blackfyre,' reflecting the Targaryen tradition of sister fighting alongside (or alternatively against!) brother, both echoes of the Targaryen house words 'Fire and Blood.'
Incidentally, a House's 'Words' are so much more than a mere motto, as you correctly point out. Not only are the 'words' intimately connected with the sword, history and ethos of that House, the 'words' of a particular House are traditionally shouted as a battlecry when riding forth swords aloft into the fray of battle, in order to assert ones allegiance, to muster up battle courage, and to 'ward' off ones opponent and fend off any ensuing personal harm (or ruin to ones House), thus yet another connection between words/wards/swords/runes/ruins.
When 'all' is revealed, and Dawn resurfaces, it will no doubt have a major role to play in the promised, eponymous 'War for the Dawn' (especially since GRRM is so coy about it). Dawn was forged from the heart of a fallen star. Having fallen from outer space and glowing with an otherworldly milky-white bluish light, the implication is that Dawn, though not of Valyrian steel, is nevertheless equally if not more magical than the rest. In Dawn, we have the combination of a number of elements we've mentioned. It's a sword, word, ward, rune, and ruin all-in-one (having been forged from a burnt out piece of rock; a fallen star is a kind of ruined star which is powerful nevertheless...'ruin' is etymologically derived from the root for to 'fall' or 'collapse'). N.B. 'the broken tower' and the fallen Star-k (see @evita mgfs ).
As an aside, the mention of the 'Rhoynar' reminded me of our 'rune/ruin' puns, considering its similar sound. Could there be something in it? In addition, the Rhoynar are a ruined culture, an 'orphaned' people, who according to the wiki used 'water magic' and other spells to fend off danger (which is a kind of 'rune'!) as well as being related to 'swords' in a way, considering they were reportedly the first to introduce the secrets of working iron into weapons. With their relationship to Nymeria and Arya, their lore is bound to resonate with Arya's arc later on, if it doesn't already (her magical warging powers and close association with water, e.g. in Braavos).
In the text we see many warriors riding off into battle or competing in the lists armed with not only their swords and shields, but traditional armor engraved with runes for protection:
Here, the 'runes' and 'swords' are juxtaposed in the circle of power represented by the replica of Torrhen's crown (the original currently missing-in-action). Note again as above, the 'runes' are associated with the metal 'bronze.' There appears to be something magical associated with bronze, the metal exemplifying the age of the First Men. When bronze oxidizes it acquires a green sheen (which is the color of nature besides), so bronze and green are the colors associated with the First Men, the Children of the Forest, and Meera and Jojen Reed, the latter Reed a powerful Greenseer and Bran's guide, the former his protector (both therefore exemplifying the 'warding' function). Bran's words are strangely prescient when he says of the Reeds:
In the passage above, the Reeds arrive to swear their 'words' to Bran, words which are coincident with their 'swords' ('sworn swords') and 'wards'...The Reeds described as 'slender as swords' swear fealty to Bran and promise to defend him come what may. The final ritualistic utterance of the three elemental couplets (earth & water; bronze & iron; ice & fire) assumes the enigmatic grandeur of some kind of magical incantation warding off evil and division.
The magical 'greensight' is always associated with 'bronze scales' and the color green (the three-pronged spear mirroring the three-pronged fork of the Trident). The two Reeds and crannogman are characterized as three (the lizard-lion has three heads?!) fierce and furtive little 'lizard-lions' with their bronze-green scales, 'leathery skin' and sharp 'teeth' paddling through the water...which reminds me of another magical reptilian relation:
Like the 'lizard-lions' of the Neck (what we'd call crocodiles or alligators), Daenerys's dragons are living fossils -- words, swords, and wards (and runes and ruins). Magical beings, born of blood magic, they like swords or people have names. Like flaming swords, they are Dany's primary weapons. They are her 'wards' in a dual sense, first as her 'children' for whom she is responsible, and reciprocally as her protectors. I'm not sure of the significance, but Rhaegal with his bronze and green scales, associated with the foliage of summer and fall, echoes the descriptions of the Reeds and those other 'children,' the Children of the forest.
Bones (a person's ruins) as runes. Rattleshirt, the lord of bones, uses the bones/skull/teeth of his enemies from which to draw strength and intimidate further enemies. Hence, the use of the teeth (dental acuity) and skull (mental acuity) as protection.
The following -- Robb and Catelyn's visit to the Ruins of Oldstones -- is the most important passage of all, when it comes to considering ruins in the context of runes, words, wards, swords. Indeed, a rune or ruin is an 'old stone'! I find it particularly poignant as Robb receives an intimation of his own mortality (as he poetically overlooks the Twins), and contemplates the same with a stoicism belying his youth. When Robb pauses in 'somber' contemplation 'in the [ominously] gathering dusk' beside the grave of the king, he becomes a 'seer' seeing deep into his past, the story of the ascension and subsequent destruction of the Kingdom of Mudd of the First Men mirroring his own doomed kingship, not hesitating there but seeing beyond his own death and making provision for this eventuality, something which Catelyn refuses to entertain. Although at some level she too admits their precarious position, musing on life's fragility and the futility ultimately of all human endeavor in the face of the erosion of time and the elements "We're all just songs in the end. If we are lucky.' Language is the fundamentally human way to ward off the passage of time and preserve human culture -- our primary weapon (this concept is essentially a recapitulation of Bloodraven's weirwood lessons), and is a common trope in literature, as a reflection of the author's ego contemplating his or her own mortality.
The passage reaches a climactic moment, at once triumphant and heartbreaking, when Grey Wind jumps up on the grave and takes his position besides the king (here, both the dead king and Robb the soon-to-be-dead king); the stony sepulchre, the wolf and Robb's 'cold' face reminding us of the Kings of Winter with their stone direwolves holding eternal vigil on their tombs in Winterfell crypts: 'Grey Wind leapt up atop King Tristifer's crypt [Latin tristis 'sad, mournful, sorrowful, gloomy'], his teeth bared. Robb's own face was cold...' In that moment there can be no doubt: Robb, Grey Wind, and Catelyn are doomed. This tableau is reminiscent of Ned's dream which came to him shortly before his own death, perhaps announcing it:
Oldstones:
En route to their final destination (symbolic in itself) 'the Twins,' Robb and Catelyn stand amidst the ruins in the rain (which is of course a 'twin' of how they'll soon end at the Twins, ruined, on another day of relentless rain in a rain of arrows to the Rains of Castamere, another ruin) contemplating the potential ruin of the Stark family and its aftermath. In response, Robb wishes to ward off this unpleasant possibility by securing an heir of his choice -- namely Jon. However, Catelyn blinded by her jealousy and hurt can not get beyond seeing Jon as a sign of ruin. If we look closely at this scene though, there may be a subtle hint already present of Jon as ward, savior, and king, in that the king's 'likeness' is overgrown by wild roses, a living symbol of both Lyanna and Jon.
Robb argues that a 'ruin' may be easily turned into a 'rune' so to speak by a word, in that a royal decree can easily legitimize a bastard and secure his legacy. While we're on linguistic puns, Robb uses the word 'issue' which may refer to an heir as well as a book. Catelyn argues in bad faith that a Snow would ruin house Stark, a bastard is tainted, a ruined version of trueborn, and comes up with ridiculously far removed relations as insulting alternatives in an attempt to ward off Jon from her consciousness as is her wont ...But most of all -- and this is key to understanding what makes Catelyn tick -- Jon is a reminder of her own ruin -- of how she is the insulted party, after Ned in her mind irrevocably broke his vow/word to her and ruined his honor and hers, something she can not and/or will not overcome. Robb is right, she is lying to herself, although with her characteristic self-righteousness she claims 'all I have done is speak the truth'... She was and is and will always be Lady Stone Heart, literally and figuratively a heartbroken, ruined woman:
Books/words as ruins, 'falling to pieces...crumbled away...buried' ;as well as runes...Sam the Slayer of knowledge is digging through the books (the mention of 'runes on rocks' suggests that all research is a kind of archaeological excavation) looking for the answer to defending themselves against the Others. i.e. finding a rune is like finding a key to unlock the knowledge of how best to ward off the Others (again, Sam as the gatekeeper via words as swords).
Here Sam seems to have a literal hunger and/or thirst for knowledge; he also appears to be somewhat 'bloodthirsty' perhaps, as he 'licks his lips' thinking of the enemy!
Tormund relinquishes his rune-engraved golden (not bronze interestingly) armbands, historical artifacts 'ruins' really, to stand in stead of his word as payment, thereby signifying his pact with Jon ('rings' also symbolizing a marriage of sorts between the Night's Watch and the Free Folk). The allusion to the ring he wears around his 'member' is a reminder of the potency associated with words/wards/swords (phallic imagery) and runes/ruins. Significantly, Tormund though on the surface trusting Jon to honor his word, nevertheless holds onto some of his own power by withholding that final ring...to ward himself from harm, should either Jon and/or the Night's Watch rescind on their troth to allow a peaceful crossing.
Tormund's shrewd caution and saucy banter reminds us of the possibility always inherent in words/wards/swords and runes/ruins, that they may fail us, or worse turn treacherous. Thus, to respond to your question regarding Thoros ruining swords vs. runic words (the latter which were able to ward off death), this is evidence that there are both -- true and false -- words/wards/swords and runes/ruins which make an appearance throughout the text. To start, Thoros' sword reminds us of that other fake sword, Stannis's Melisandre-anointed 'Lightbringer' which flashes very prettily emitting light but no heat. She's a seductress, and this is one of her tricks, just an empty 'glamor' (however, as in the case of Thoros, this doesn't necessarily exclude any other of her powers from being 'real'). Sincerity and deception may co-exist in one person -- isn't this GRRM's favorite theme? To cite a few other examples:
Is this the real thing, or an imposter? Was Mance lying, or telling the truth? It's implied that Sam has the Horn, which would be fitting seeing as he's the master linguist (the horn speaks in a secret language like the language of ravens with which Sam has been associated), the maester of runes (as well as a boy who was 'ruined' by his domineering father), the slayer of knowledge, the Huntsman Tarly striding forth...
This is a false queen, false crown (the irony that Robb too wore a false crown when he proclaimed himself King of the North...Torrhen's crown is elsewhere...like Dawn, I'm pretty sure it'll have to resurface before we're through...).
The instance you mentioned. The sword is an imposter, masquerading as Ice (Sansa notices the difference instantly). Although Ser Ilyn does not speak, the sword can be said to speak loudly (its ornamentation quite garish, ostentatious and over the top). Likewise, the runes are flashy and 'bright' (engraved in silver this time...?significance of the metals), nevertheless they do not speak true, considering how they are supposed to ward Joffrey from danger and bless him on what is supposed to be his most blessed of days, his wedding day. On the contrary, they hint at treachery and presage Joffrey's death, i.e. ruin (echoing our motif of the cheeky poisonous gift, Ser Ilyn is literally 'presenting' it to him) when the ruby eyes 'wink' and the dragonglass 'skull grins' at him in mockery. So the 'specter is at the feast' and the sword partakes in the grim farce. Another way of looking at it is that the sword does indeed speak true, considering Ser Ilyn and the sword represent the King's Justice, and Joffrey has not been a just king! Joffrey has made a mockery of the monarchy and the mummer's farce at his end is fitting.
So, try ones best, sometimes the protection doesn't come through for one. Also in this passage is an allusion to Sansa herself as false. Sansa is more interested in flashy heraldry than the actual people behind those masks (cf. The Hound vs. Sandor). While Ser Robar is carried off 'dazed and unmoving,' Sansa is unmoved, with 'eyes only for Ser Loras'. This is a very important lesson: For all this fine talk of words/wards/swords and runes/runes-- we should always bear in mind that symbol does not automatically equate with substance -- which is of course the whole crux and crutch of Sansa's arc.
P.S. Among other interpretations, the burning of the books can be understood as an 'ignition of understanding'!