Rilla Roo was one of the newcomers among Crash Bash’s eight playable characters.
The 2000 party game’s roster includes Crash, Coco, Tiny, Dingodile, Doctor Neo Cortex, N. Brio, Koala Kong, and Rilla Roo. Rilla Roo is the only character in that original playable lineup explicitly introduced as a newcomer, making him the canonical answer to the question.
Rilla Roo was created for Crash Bash because the developers wanted another suitable player character beyond the existing Naughty Dog cast. His design combines features of a gorilla and a kangaroo, reflected in his name and appearance. Cerny Games contributed to the concept, while Eurocom’s character artists developed the design.
The other options belong to different parts of the franchise. Emperor Velo is associated with Crash Nitro Kart, Nina Cortex debuted in Crash Twinsanity, and Crunch Bandicoot was introduced in The Wrath of Cortex. None was one of Crash Bash’s original eight playable characters.