Did someone say "Gladiator"? I think Redcat Gladiator has a nice ring to it.
Other ideas, Not sure if any have been mentioned.
Renegade
Katana
Samurai
Rapier (sword)
Rage
Regulator
Reaper
Some Latin ideas maybe?
Lacerta (lizard)
Ragana (ray)
Rasurus (razor, or just use Razor)
Japanese?
Raiden (God of Thunder)
Rokuro (sixth son)
Ronin (samurai without a master )