Both in that Leviathan is the representation of envy, and a representation of an all powerful and massive beast, I thought it fit. Considering his size and motivations, which I won't bore with, but yeah. I always rather liked the name myself. :3
Would it be acceptable to you, Viathan, to have my Sith character and yours go at it at some point? I'd love to see them in a hypothetical duel where they'd test each other in combat.