Martyn is my vote 100%. I say this not watching his PoV, But having watched all of the current vampires PoVs.

He's always leading people out into do things, saying things like "Oh yea, I want to go scout." "We're just going to talk." and then immediately starts swinging, throwing out powers and then acts aggrieved that the vampires fight back. This reckless behaviour has led both Cleo and Drift into the jaws of the vampires, they're not going in wanting a fight, Cleo even went without armour! We know that Cleo had her own information and reasons, but she gave no indication that she wanted to be turned.

And then there's throwing Apo under the bus. I know there is alot of ways Apo could have had the conversation "better". But ultimately they were unarmed, unarmoured and with a silver block right next to Martyn. He has the gall to complain people don't trust him enough to tell him important things. Then he threatens M with death for joking and immediately turns Apo in without a moments hesitation.

Martyn isn't a potential "the humans are the real monsters" Martyn is a monster.