This is good but could made it calamities are birn spirits from other creatures or a races that was hunted and experimented on by humans as it make sense why they desire slaughter n kill n hatem that way u give Mugen a history. And restriction if he uses his power then mc cant or wont have 8 unlimited. But have certain level make it so unlimited is his power but other abilities and power is mugens and so cost happens. And mc father is one of bad ones involved that way it tests his faith in humans aswell