Birthday: January 12

Lan Sizhui is a disciple of the Gusu Lan Sect.

Originally named Wen Yuan (温苑), Lan Sizhui is the last remaining blood descendant of the now-extinct Qishan Wen Sect. Taken in by Wei Wuxian along with remnants of the Wen clan to the Burial Mounds, he lost his home for a second time in the first siege of the Burial Mounds. Discovered by an injured Lan Wangji who came searching for Wei Wuxian's remains in the aftermath, the then-three-year-old boy fell into a high fever and lost all memories of his past. He was then re-named as Lan Yuan (蓝愿) and later presumably given the courtesy name Sizhui in the same year that Wei Wuxian returned to the living world.

(Source: Mo Dao Zu Shi Wiki)