Immortality wasn't anything unusual, not since the skrita took control of the world during the Switch. Unfortunately, immortality wasn't unfamiliar to Luka either, despite his (somewhat dubious) status as human. For him, it was a curse, one given to him by the same monster that murdered his family and left him floundering and lost.
More than two hundred years later, Luka meets Kricket, the apparently not-so-mythical elemental of ice and wind. Even more unlikely, she seems to have answers to questions he'd long since stopped asking.
Kricket introduces him to a potentially world-ending war that he hadn't even known was happening, reveals that his family's murderer is a part of it, and then gives him the opportunity to do something about it.
Luka joins the fight.
His fellow soldiers are about as soldier-y as he is. There's Ryker, a bubbly human with abhorrent nick-naming abilities. Kōan, a crow shifter that is a little too willing to use her sword. Atlas, a cat demon who writes textbooks for fun, and finally their healer, Tsuna, the woman who graciously welcomed him into her home and only threatened bodily harm occasionally.
Joining a war was always going to change things, that was the point, but he never could have imagined exactly where it would lead.