He isn't his father its another man completely, maru father is less tall and more "recent"
well that theory was going for a while a while back when i looked at the comments so
Yes i read it too but it's not the father from the start i assure you they mistook him cause someone named the chapter when he first appear "is he maru father?" but was only a joke lol
could it be hanmaru was actually adopted (or kidnapped) from the yellow zone place by his "dad"?
I think the actual mother adopted him after his father disappearance and maru for some reason don't remember well what happened or for the shock or someone doing
so technically he ain’t his father… or did he reincarnated as his father and remembered his past or smth? inch resting