More lore about v!Mig:
He used to be a composer. He loved it, frankly. The way music came together, the way no instrument on it's own could fully triumph over the orchestra. It reminded him of himself. He was a young vampire too: his mentor had offered him eternity, to learn all the melodies and instruments, and he couldn't help but take it.
But as a young, technically jobless man, he was drafted.
Eventually though, the whole memory thing proves that he would NOT make it as a soldier, so he's moved to a saboteur. Who wouldn't trust this fool after all? So, the man is taught how to use poison, how to sneak behind enemy lines. He spends most of his time with the medics.
Mig doesn't know how to feel about the vampirism. On one hand, he could prevent the soldiers or medics from dying: he could keep them safe. On the other hand, he fears that it's not his right to turn someone immortal: that he hasn't seen the whole picture yet and therefore shouldn't spread vampirism.
He confides in one of his friends: Legundo. At the time he was also young, also free. They talk about it. Talking is really all they can do. Legs is pretty used to his erratic behaviour, and the concept of vampirism is interesting! The moral side of it is the part they're both worried about. The war was too much to think about: it was easier to distract themself with empty moral talk.
They make a promise. If times are good, Mig would feed off of him just so Mig wouldn't starve. If times were bad, though, they'd both hold themself to the same rations as everyone else. So they went forwards.
The war lasts longer than anyone thought. Mig should've died many times over the years, but vampirism gives you an uncanny ability to keep coming back. It leaves him a bit of a shell of his former self. He seems to switch between emotions and ideals, like he's being replaced. Yet, he's not: it's still Mig. Only the doc seems to really understand that.
Meanwhile, Legundo has begun to hate himself over all the people he couldn't save. All the times that his training wasn't enough: that the bleeding was just too much. The idea of offering his lifeblood to Mig, the idea that he can repent, he starts to obsess over it. He wants to repent. He wants to better and he can't be better.
The only friend that's gotten this far, for either of them, is each other.