The Source of the Mad King's Obsession (Theory)

[AntZen]

This is my first time posting in a forum, but I have a theory about why the Mad King was so obsessed with fire.

It's been said that every time a Targaryen is born, the Gods flip a coin. That's because Targaryens tended to go mad due to their policy of inbreeding, wedding brother and sister. It's also often stated that the Mad King, Aerys II Targaryen, wasn't mad from birth. His madness came on in his later years, and in fact, early on was considered a benevolent ruler. In his increasing madness, he became more and more obsessed with fire, between ordering his Pyromancers to stockpile Wildfire under King's Landing in thousands of casks, and declaring fire his champion in a trial by combat against Rickard Stark. 

So what caused the Mad King to slowly lose his mind and become obsessed with fire. We're told that it's Targaryen Madness but what if it isn't. We've met another character who was normal and kind suffer a change in personality and mental health. We know that Hodor didn't start off as Hodor, and in fact was a perfectly normal boy in his youth. It was only when Bran Stark warged into the past as the Three Eyed Raven that he affected Hodor, causing him to obsess over "Holding The Door".  It's possible then that Bran will at some point, Warg into the Mad King's past and cause him to obsess over fire as the Mad King goes insane. But why would he do that?

Well, from what we know about wights, normal weapons are only mildly effective. Being slashed and cut as an undead doesn't stop them. However, fire seems to worst most effectively against them, and in fact might be the best weapon to use against the hordes of the Army of the Dead. And we've been assuming that Danerys' dragons will be crucial to that fight, however the Dragons aren't immortal, and Cersei and the Night King could both devise ways to defeat them (Spoilers: In fact, one of them has already killed a dragon). What happens if the final battle occurs without any Dragonfire?

If Danerys manages to take King's Landing, only to face an army of Undead marching south, she'll need a substitute for Dragonfire. Thankfully, there are caches all over King's Landing filled with Wildfire! A substance that burns like Dragonfire. It's possible that Bran, as the Three-Eyed Raven will be the architect who sets all this up so that the living win the final battle. That Bran will Warg back and basically start the entire chain of events that leads to the conditions necessary to win against the Night King. 

What was it that Jaime said the Mad King kept repeating, obsessing over, and lost himself to even as he died? "Burn them all".