A character in the light novel Grandmaster of Demonic Cultivation/Founder of Diabolism/魔道祖师. There is also a donghua adaptation, a drama adaptation called The Untamed/陈情令, an audio drama adaptation, and a manhua adaptation.
Lan Sizhui, or Lan Yuan, is the most adorable junior in the whole show, the son of everyone’s favourite gay protagonists, Wei Wuxian and Lan Wangji. At one point in the drama, he said (translated to English), “I understand that you were tragically poor in your past life,” which proves that he is amazing. He also was the only Lan Sect junior to be praised (not out loud) by the main character when they met with neither realising who the other was. This shows that Sizhui is the best and smartest junior, much superior to the young mistress Jin Ling who was spoiled as a child.
When Sizhui was a toddler, he was addressed as A-Yuan, with his name being Wen Yuan. When he first saw Lan Wangji, because he was lost and scared, he clung to Wangji’s leg and called him ‘dad’. In the burial mounds, he was buried in the ground with radishes and told that he would grow faster in the ground, and other children might even sprout to play with him. In the Gusu Lan Sect, he was buried under a mound of rabbits. All of these incidents show that Sizhui was adorable as a child and still is.
All in all, Sizhui is the best.
Lan Sizhui kindly persuaded Wei Wuxian to return the array flag, a more effective method than Jingyi’s threatening.