In the original Streets of Rage, they make their first appearance as bosses on stage 5. They are very acrobatic, evasive, and clever at delivering their attacks. In the third game they appear as bosses on Stage 2.
They appear as palette swaps of Blaze, bearing almost the same moves. Despite looking petite, they can deliver some of the most damaging attacks in the game; in the hardest difficulty, a single attack can cost 80% of the player's health. It is very difficult to hit them with regular moves, as they'll constantly do backflips which render them invulnerable whenever the player attempts to approach them. A good strategy is to keep one's back turned, then using a back attack (attack+jump buttons) whenever they approach.
In this game they are given a major overhaul. Instead of looking like Blaze, they appear as acrobats in skintight suits. Besides most of Blaze's moves, they also use several double-team tactics that can knock off huge chunks of health. Unlike their original appearance, they will successfully land and take no damage if tossed. They only appear in Stage 2, in the dance club's private bar.
In Streets of Rage 4, through the survival mode in the Mr. X Nightmare DLC, they appear in their Streets of Rage 3 forums. They can appear as both regular enemies and bosses.
- Their US names are a parody off Mona Lisa, a famous painting.
- Onihime (鬼姫) means Demon Princess in Japanese, while the name Yasha (夜叉) refers to an ancient class of usually-benevolent spirit from Indian myth.