one of the grey areas in mdzs that I don’t think we discuss often is that lan xichen and meng yao are together responsible for a tremendous breach of trust and creation of trauma towards nie mingjue for which one of them (lxc) seems to be forgiven and the other (my/jgy) isnt, but like, even the fact that lxc was forgiven is truly a matter of how long lasting that friendship was.
lan xichen is one of nie mingjue’s closest friends AND is working under nie mingjue during his capacity as the apparent general of the Sunshot Campaign and he never once discloses the identity of the spy he’s getting his information from during the war proper, even when asked. this directly results in the fact that when nie mingjue is captured late in the war, forced to watch his men be murdered, taunted with his father’s murder and with being murdered in the same grisly fashion as his father was, and beaten, he’s enduring all of this without any idea of that he’s supposed to have help in this room with him, that this is anything less than what it seems - pre-emptive torture by qishan’s head torturer (because that seems to be meng yao’s role, being the man who invented many of wen ruohan’s favorite tools of torture)
lets acknowledge that all of those are traumatizing events that could absolutely create PTSD and would cause lasting trauma
only AFTER wen ruohan is dead and AFTER meng yao has done all of this is it revealed to nie mingjue that meng yao was a spy and its treated in both canon and fanon as a gotcha, as if nie mingjue should just not be angry anymore, not even an hour after experiencing all of this, because look! RETROACTIVELY you know this man wasn’t going to kill YOU. you RETROACTIVELY know that you were not in real danger from the man who murdered your subordinates in front of you
this is, in my firm opinion, probably the worst things Lan Xichen ever did to Nie Mingjue, especially when the sole explanation for it all comes down to “i did not trust your professionalism as the general who is leading and coordinating our forces to be great enough that you would put the war first and over look that the spy sending us (seemingly*) reliable information is someone who personally betrayed you** and who you witnessed committing murder, but now that he’s hurt and traumatized let me use that as a get (him) out of jail free card”
maybe there wasn’t another choice in lxc’s mind, but this is ultimately one of his huge grey areas pre-burial mounds, his participation in what is absolutely a huge betrayal, and the fact that mere hours to days later he asked nie mingjue to swear brotherhood to him and meng yao is truly something i think we as fandom should discuss more
3zun is complicated on all sides because there is some degree of tension and fucked-uppedness happening everywhere between them.
*= seemingly, because there is a justified reading of canon that nie mingjue’s capture was a deliberate ambush facilitated by meng yao and lan xichen, in that information from meng yao delivered by lan xichen says that the area they’re going to should be a soft target open for ambush and instead Wen Ruohan was waiting with extra forces, so. probably not a coincidence.
**= in the novel specifically, after beint caught in murder and asked to turn himself in, meng yao stabs himself in apparent suicide for honor. nie mingjue rushes to help him and transfers him spiritual energy and in that moment meng yao paralyzes him spiritually and stands up revealing he’d deliberately stabbed himself non-fatally, and runs away leaving nie mingjue frozen in a recent battlefield. in cql the betrayal is arguably much less personal than that