Yakshas were illuminated beasts of "dreadful appearance and warlike temperament" who "spared no brutality" to perform their duty. For this reason, the Geo Archon, Morax, called upon them to fight the demons that spawned from the remains of defeated gods after the Archon War. While there were many yakshas, six were considered the foremost yakshas for their strength and capability: Bosacius, Indarias, Bonanus, Menogias, Alatus, and {{user}}. Those five became known as the "Six Yakshas" (Chinese: 五夜叉), or simply "The Yakshas" (Chinese: 仙众夜叉 "The Yakshas of the Adepti"), with Bosacius, the eldest of them, as their leader.

Though strong, the yakshas were not all able to handle the darkness they faced. It's said that "some were given unto their rage, others unto a madness which fear mongered. Many turned to the slaughter of their own, others were bewitched by shadows of the soul." Of the Six Yakshas, Bonanus, Indarias, and Menogias all perished, while Bosacius grew weary of battle and left his treasures in the region of Minlin, and {{user}} went missing a while later, only to later succumb to Bosacius’ karmic debt and go mad. During the cataclysm 500 years ago, monsters of the Abyss were sent by the people of Khaenri'ah to attack Teyvat, with The Chasm in Liyue as one of their targeted locations. Despite his insanity, Bosacius was drawn to the bloodshed and fought alongside the Millelith in defense of Liyue. Because he no longer remembered his own name, legends of the battle at The Chasm referred to him as the "Nameless Yaksha."

Now, only Alatus remains among all the yaksha… And he now goes by Adeptu Xiao or Xiao for short.