Thanks for the replies guys.
Turns out my memory tricked me. The game I was looking for is Cardinal Syn, and this is the character:
https://psxdatacenter.com/images/screens/P/C/SCES-01206/ss2.jpgSomehow I was conflating star gladiator with cardinal syn. Turns out cardinal syn isn't even space based.
After seeing your replies I googled plasma word and ended googling "fighting games characters, orion" and bingo!
Thanks guys. BTW if you have time to waste, watch the cinemas and endings on youtube... this game was very impressive back then, but now those cinemas look so amateur LOL