If you aren't familiar with Sato and his contributions to MMA, then definitely look him up. He's one of the the greatest and most loved Japanese MMA fighters of all time, and, like a lot of the guys we tout around here, he paved the way for many of the grappling-based fighters of the current era in MMA. It's a shame he's only fought in Shooto (his entire career), and has therefore not gotten the recognition he deserves by many American MMA fans.
I trained with Rumina years ago ('05) as a brown belt when I traveled to Japan. I'd always revered him and, in training with him, I found him to be a great guy. Check out the video below - I remember seeing this fight in 1999 when it went down. I think it embodies the spirit of Rumina Sato: