Jingliu

Once the sword master of the Xianzhou Luofu, as well as Jing Yuan's mentor. After succumbing to Mara and going insane, she managed to escape Starskiff Haven in the Year 7380 (Star Calendar) and easily froze all the Cloud Knights sent after her before Jing Yuan finally confronted and defeated her in battle. However, she managed to survive the encounter and traveled the galaxies outside the Luofu for centuries. At some unknown point, Jingliu "made a deal" to regain her sanity, which Luocha has proposed to be the solution to mara. (Source: Honkai: Star Rail Wiki)