People aren’t rational beings. He, of course, wouldn’t hurt his liege lord, but a foreign woman influencing your lord? She’s the perfect scapegoat for his monkey brains at that moment. Dude lost four sons, he has to cope with the fact that he willingly let them all go into battle for a man whose odds of becoming the king are very low.

Correct me if I’m wrong, but before he drowns he has no such compulsions to kill Melisandre even as the battle is going to shit and he witnesses the death of his sons. He knows this would be treasonous, and Davos would not commit treason. It’s only after the drowning that this compulsion arrives.

It seems his personality change was the most minor and temporary, possibly because he drowned the least badly.

Also because I don’t like this fact. ‘Least Badly’ is not the modus operandi of the gods in ASOIAF. The magic in ASOIAF is cruel, weird, erratic, costly and full of mockery. I don’t think deep ones would just leave him like that. And I don’t think martin meant it and if he did, I’d chalk that up to “overwriting”. Though, he’s good at avoiding that. (so far)

I would update my theory a bit here and word it better. I instead posit the severity of personality change has to do with how strong of a identity/ego the person had before drowning. Similar to how hard it is to warg a human vs. a Hodor (because Hodor has been “emptied out” of ego/identity. Patchface was a child who was raised as a slave, hence why he was totally wiped and made full Deep Ones thrall. Aeron was 16 and still a youth, but a bit more developed in his identity as a Greyjoy. He also had a surrounding culture of Deep Ones worship to calibrate himself to, a context in which his hallucinations and delusions made sense and in fact were revered by others. Patchface is mocked and seen as crazy, Aeron is seen as prophetic and wise because of where he is.

Davos is middle aged, very comfortable with his identity, very secure in his family and loyalties. He is probably the hardest type of man to manipulate in this way until he goes through destabilizing grief.

I don’t think the Deep Ones “Mind Control” directly per se, they seem to instead implant images and visions and manipulate people in the same way that say, Rh’llor manipulates Melisandre or the Three Eyed Raven manipulates Brann. The drowning just creates the psychic link that allows the transfer of these images.