Sei by Koichi Ohata
Koichi Ohata has worked both as a Designer, and a directory on such notables as MD Geist, Gunbuster, Genocyber, and most recently Bakuretsu Tenshi (Burst Angel). I met Mr. Ohata at PMX and where he graciously sketched this for me.
The character of course is Sei from Bakuretsu Tenshi.