I believe the text supports Mance writing the pink letter.  Here I will discuss the evidence. I do not claim to know Mance’s motivations or all the details. I believe at this point GRRM has not given us enough info to know everything.   Let’s start by discussing why it is not Ramsay. 1)   No seal, only a smear of wax, no skin, no evidence it’s written in blood 2)   Threats in letter do not match his MO, e.g. heads on spikes 3)   Language used in the letter is not consi