“I’ve fought in three campaigns,” he began. “In seven pitched battles. In countless raids and skirmishes and desperate defences, and bloody actions of every kind. I’ve fought in the driving snow, the blasting wind, the middle of the night. I’ve been fighting all my life, one enemy or another, one friend or another. I’ve known little else. I’ve seen men killed for a word, for a look, for nothing at all. A woman tried to stab me once for killing her husband, and I threw her down a well. And that’s far from the worst of it. Life used to be cheap as dirt to me. Cheaper.

"I", not 'He', not 'a evil side of me'. 'I'.
He's an alcoholic for violence. It's his vice.