Ken Kurenai (紅拳)
Background
In battle he is a great strategist, being able to see through his enemies techniques and reveal their weak spots. A highly skilled martial artist, he trained in Muay Thai alongside Shadow since childhood, developing an early rivalry with him. Finally, one of his most common traits when fighting is that he is never willing to give up, even when having sustained grievous injuries (such as when Koumei tore off one of Red Baron's arms, or when Shadow ripped of some sort of cooling device out of Red Baron's chest); however, it is due to this fighting spirit that he is also able to win his most difficult fights (being able to use his spiritual energy to give the Red Baron a great power boost). It is worth noting that his true name may not be Ken Kurenai, due to the fact that when meeting Kumano in the first episode, he looks at a bunch of roses before saying his name (Kurenai being the Japanese word for rose, and Ken taking some time before coming up with the name). (His name is translated as "Kent de la Rosa" in the Spanish version.)
(Source: Wikipedia)