Lan Huan (蓝涣, Lán Huàn), courtesy name Lan Xichen (蓝曦臣, Xīchén) is the current leader of the Gusu Lan Sect and one of the Two Jades of Lan alongside his younger brother, Lan Wangji. He is also known by the title, Zewu-jun (泽芜君, Zéwú-jūn). He is at most three years older than his brother.
Lan Xichen is tall and slender. His eyes are gentler and darker than Lan Wangji's. He and his younger brother are described as "mirror images" of each other. 
In animation, Lan Xichen has long black hair and the same gold eyes as his brother. There are notable differences in his and Lan Wangji's appearances: Lan Xichen does not have bangs that go over his ribbon and his is usually seen with a smile.
He has a warm and gentle personality that contrasts to Lan Wangji. He is shown to be trustful and loyal to others. His kindness is not limited to those of his status, as he has demonstrated no prejudice towards a person's social status or background most strongly evidenced by his close relationship with his sworn brother Jin Guanyao, whose status as a prostitute's son was never belittled or looked down upon by Lan Xichen. However, Lan Xichen does possess a temper and is deeply protective of those he cares for, especially his younger brother Lan Wangji. His anger is best seen when speaking towards Wei Wuxian, whom he developed a grudge against because his own brother had defended Wei Wuxian and betrayed the Lan sect to protect him, resulting in thirty three whip scars. He even refers bitterly to Wei Wuxian as "the only mistake Lan Wangji made in his life".
His birth name is Lan Huan (蓝涣, Lán Huàn).
Studying at the Cloud Recesses
Escape to Yunping
Sunshot Campaign - Hejian Front
Taking the Vow of Brotherhood
Wei Wuxian's return
Night-Hunt in Tanzhou
Jin Guangyao's true face
Incident at Guanyin Temple
Lan Xichen is close to Lan Wangji and is the only one capable of reading his stoic face. Lan Xichen was horrified to learn that Lan Wangji had hidden Wei Wuxian and even more so when Lan Wangji attacked their uncle who raised them along with betrayed their sect and attacked thirty three elders to do so.
When Wei Wuxian first went to study over the Cloud Recesses, Lan Xichen was very polite towards him. Seeing how close and dear Wei Wuxian was to Lan Wangji, he seemed to have wanted to preserve and deepen the relationship between the two as his brother was usually never close to others. However, Lan Xichen's opinion of Wei Wuxian became strained after Wei Wuxian became the Yiling Patriarch. Lan Xichen was horrified to learn that Lan Wangji had hidden Wei Wuxian and even more so when Lan Wangji attacked their uncle who raised them along with betrayed their sect and attacked thirty three elders to do so. He still deeply loves his brother and forgave him, but grew to develop strong bitter feelings against Wei Wuxian, being the only person he has ever demonstrated outright anger towards. In chapter 99, after revealing how much Lan Wangji suffered because of his love for Wei Wuxian, Lan Xichen refers to Wei Wuxian as "the only mistake Lan Wangji ever made in his life". Despite this, the two did have a decent relationship as Lan Xichen helped Wei Wuxian escape when his identify was discovered and he was being pursued by other cultivators. He showed amusement at Wei Wuxian's romantic confession to Lan Wangji at the Guanyin Temple, commenting politely that it was not the right time to confess. He also tried to warn Wei Wuxian when Nie Mingjue was attacking them and showed concern for his safety, though this could be because of his relationship to his brother. It remains to be known where their relationship stands as Lan Wangji has married Wei Wuxian, though it is most likely a neutral one.
Lan Xichen is the one who could be said to be most acquainted with Jin Guangyao's niceness. Lan Xichen did not hold his roots as a prostitute's son against him. In return, Jin Guangyao had repaid his kindness many times over, helping him rebuild the Cloud Recesses, supporting the Gusu Lan Sect, and so on. Under normal circumstances, Lan Xichen would never suspect Jin Guangyao - because the Jin Guangyao which appears before him has never acted in such a manner to invite suspicion.
Lan Xichen had a friendly relationship with Nie Mingjue. Despite the latter's hate of Jin Guangyao Lan Xichen was able to convince him to take on the vow of brotherhood. Lan Xichen was also accepting of Nie Mingjue's bad temper. This good relationship extended after Nie Mingjue's death, for Lan Xichen took care to protect the Qinghe Nie Sect under Nie Huaisang's lead.
Abilities & Weapons
- Lan Xichen ranks first on the list of best-looking young men in the cultivational world.
- As part of the Lan family genetics, Lan Xichen also gets drunk with one cup. According to the author, when Lan Xichen gets drunk, every sentence he speaks ends with three exclamation marks.