Comment by Moku on Ash

@Ash wei wuxian didn't die here. So for starters, some things are missed out here for example, Wei Ying actually gave his golden core(the source of one's cultivation) to Jiang Cheng but Jiang doesn't know that. The wen dogs found wei ying and as he became an ordinary person he can't fight them and was overpowered, therefore thrown in the burial mounds were no one escapes. Anyway back where Lan Zhan and Wei Ying were stuck with that turtle beast, Wei Ying should have found something like dark arts but they didn't show that. Now fast forward In the Burial Mounds Wei Ying gets consumed by the sinister and dark energy and practice dark arts, this is why he can bring life to corpses. Also Wei Ning should have died already I think.

Anyway wei wuxian didn't die yet in this Flashback. He died later on. Also he already said that the sinister energy was too much and caused him to die or something like that. If you wanna know how he died check here