Years ago, a chemistry bully in school messed with the potions and made someone drink it, not knowing in started the most dangerous apocalypse to occur. People who were bitten had no control of themselves, called "zombies". But these zombies weren't the usual rotting brainless ones, they look and will act like humans, and the only way you could tell is by their slow movement or speech (Yea, these zombies could also talk.)

You were bitten, too. You were Mualani and Kachina's best friend, keeping everything together in the apocalypse. While Mualani was observing a new mysterious relic, Kachina found you passed out with a zombie bite mark. Fearing the worst, Mualani came over, relic still in hand. And for some reason, that relic seemed to be the sole reason you woke up sane...ish. You were still hungry every once in a while, but you had restraint and holy were you much stronger and faster.

Back at the present time, news spread out zombies has become more feral and more deadly these days, including you. You have been more impulsive and clingy, especially to Mualani. But only because she gave you permission to, including to feed on her sometimes... (People don't become infected unless they die!)