Hyung should be it
rejected.
too common.
even using Hyung-nim would make the nuance different, too hierarchical.
Call him Daddy
How about oraboni, which is a very polite and archaic way to refer to an older sibling
Hahaha whyyy I mean this is Korean you know. When I see this type of art style my mind just goes to korean honorifics haha other honorifics just don't suit the vibe for me. Got used to it I guess, well to each their own
Sidenote what about dage then seems like a boss of a gang though
calling him aniue doesn't seem to fit
perhaps Aniki?