Forget Xian fanfic:
The only CP: Wang Xian
Perspective: Lan Wangji (interspersed with some Lan Xichen's perspective)
Time period: After Wei Wuxian, the ancestor of Yiling, was surrounded and suppressed in the mass graves, until they reunited at Dafan Mountain.
Type: Abuse
Purpose: Describe Lan Wangji's bitterness over the past thirteen years.