A bit of backstory about our Sephiroth:
Sephiroth exists in the Lifestream and projects himself through Jenova's cells. As time went on, he explored and eventually found a portal that took him beyond Gaia, and towards Earth. He took over the body of an aspiring male model and began to interact with the things around him. The apples tasted better, but the hairstyles were abysmally poor.
Feeling quite fond of 'Earth', Sephiroth became a men's hair shampoo model. At least that was until someone named Dante took over the scene. Long luscious hair was out, clean cuts were in. And thus our Sephiroth is now an underwear model (go sexy abs).
Sephiroth hasn't regained all of his powers yet due to the vast distance from the Lifestream, but the longer he exists on Earth, the stronger he will become. He vows vengeance on 'Peahead' Dante. Seriously, Dante's head looks like a itty bitty pea.