Pixiv tags include パニス・レプカ (Panis Lepka?) and デューマン, and Googling those does lead to a few similar images. パニス・レプカ seems to be just the name for a particular costume, and デューマン (Deuman, according to this link) is a race in that game. This is probably a drawing of a player character wearing that costume. Removing character_request tag.
EDIT: Oh good lord, just checked the wiki for phantasy_star_online_2. That is a lot of costumes. Maybe someone more familiar with this game can check if there's already a tag for this costume?