Fergal Devitt explains the name ‘Finn Balor’:
The ‘Finn’ is from Fionn mac Cumhaill,which is an Irish translation of the name of a mythical warrior.
The ‘Balor’ is also from Irish mythology, and he was king of the Fomorians, a group of supernatural beings. The name Balor is also said to be taken from the Celtic for “the deadly one.”
I mean, sure, we’ve never heard a name quite like Finn Balor, but with that explanation, hell yeah, it’s a badass name.