Belias first appeared in the Final Fantasy series in Final Fantasy Tactics, where his name was mistranslated as "Velius", though this was corrected for the PSP remake, "War of the Lions".
In Final Fantasy Tactics, he is a Lucavi demon who merges with the fallen revlutionary Wiegraf Folles. He appears as a boss character, and is known for being one of the most challenging enemies in the game. He is often infuriatingly inconsistent however, so that after you've spent some time ranting about how impossible this ram-headed git of a boss is to a friend, they take a shot at him and defeat him easily, because he's decided to employ different tactics which leaves you looking stupid. The cur!
Belias uses powerful summon spells, and is assisted by three demons in battle.