Wen, Chao

Wen Chao was the youngest son of Wen Ruohan and leader of the Wen Clan.

[Spoiler] Because of his and Wen Ruohan's malicious intent, they caused great destruction to the Lan Clan and Jiang Clan by destroying their residences and killing the entire Jiang Clan, except the children and first disciple (Jiang Cheng, Jiang Yanli and Wei Wuxian) who went into hiding. He was also responsible for throwing Wei Wuxian into the Burial Mounds, which resulted in his own death when Wei Wuxian returned to end his clan with his new created dark arts. [/Spoiler]

(Source: Mo Dao Zu Shi Wiki)