Hmm, I ckecked the wiki again and Diamantha's story is really, really messed up. Why does she write so fucked up backstories for her uwu-wholesome-lesbian-found family-friendship story?
Keep lording that edge.
Syir is a minor antagonist in Madhouse. She is Diantha's mate, and has used violence and extrajudicial murder to keep their secret safe. Syir has been with Diantha since they were children, and at some point the two began a sexual relationship. Whenever they were found out, Syir would usually...
pokemadhouse.fandom.com
Basically, it wasn't Diamantha was interfering with the League's investigation, it was that her Gardevoir, Syir, was murdering the inspectors and hiding their bodies.
She treathened to kill all of Lily's loved ones once she and G came to investigate.
The League somehow got wind of the killings (i think? It's kinda vague) and arrest Diamantha for bad handling of her pokemon.
As Lily's writing Stockholm over and over again, it's revealed that Diamantha was actually forced into an abusive relationship by Syir, ala Ascentia. For some reason Diamantha (who is arrested?) runs to Lily for help who refuses to do so 'cus she scared that Syir might kill her family.
And of course, as caring as Lily is about abuse victims, not only doea she refuses help to Diamantha, she also contacts Syir about her whereabouts. End of page.
It's as cannon as anything else in madhouse. Just from this addition of lore I wouldn't be able to guess that Diamantha is one of Lily's favourite trainers. Just saying.
Apart of how fucked up it is that comic Lily, appearently delivered an abuse victim back to her abuser, where the abuser is a mass murderer non the less...
Also, agreed - Cynthias design really is great.