Mushas during a mounted attack
Mushas were a class of combatants. Specifically, they assaulted Jedi Tsubaki near the period when he succumbed to the dark side of the Force, until Princess Misa came to his aid and saved him.
The short film "Akakiri" from Star Wars: Visions marked the debut of the Mushas. The end credits identified them as "Musha" (武者 in Japanese), which translates to 'warrior'.