@diojoestar809 isn't the basis of dark magic in this universe tied to the concepts of sacrifice and offering. so wouldn't life drain be related to theft of power than offering in this case they offered up their force for a strength boost to their allies? the power they gain seems to come from self sacrifice or offering their own belongings rather than the sacrificing of others. this would explain why it wouldn't work on enemies.
I really hope they don't call him something stupid like, Gray Knight. How about a Twilight Knight. When you mix light and shadow, you don't get gray. You get twilight, so Twilight Knight. At the very least it sounds better the gray.
He what? Damn cliffhanger. Thanks for the update, please continue translating this manga really love it. Thank you translators can't wait for the next update.
If dark symbolises destruction and light symbolises creation and then congratulations you just acquired celestial magic and now you will be able to create star and stuff or maybe a black hole too.