Please do not take the following as offence..
From the artistic POV, not technical - the tech side is very good...
First of all he is a tad bit disproportioned -- I guess getting the FF7 model as a basis would be nice. Ears both differ in size and shape from 'proper'.. Also the nose size and relation with eye/mouth is off. The eyebrows could be shorter.. Sephiroth had different eyes, and they rather should be kept flat and drawn. And.. Umm.. No healthy man has such muscles. Even after a Sephiroth Diet. Sephiroth was a SOLDIER -- a figther, lean fighting machine, not a walking powerhouse... He has too much muscle both in abdomen, chest as in arms... It looks like taken off a DB sorta game.. Like Bid for Power or something..
Once again sorry for the straightforward answer.. They might be pointed out harshly, but they are truly little mistakes, which fixed can make wonders for the character.. Although when making a character that way you tend to rely on your own vision of him/her..
Whoo booy, now I awoke from the hiatus and when back from Germany (hello Alhexx ^^) I'll try to get my hands on Lightwave again...