[Overlord] Archie gets turned into Shalltear's Sex Toy in the Web Novel

So you heard that Archie gets turned into a sex slave instead of killed in the web novel? Well it's true. The web novel doesn't actively describe the act but it does give you an idea of Shalltear's tortures, Archie is effectively brainwashed by the time we see her again. She realizes her life as a pet was preferable to the constant torture endured by the others of her party. Shalltear gives Archie a "tail" that she gradually increases the size of. Shalltear however does not take Archie's chastity on Ainz' order not to hurt her despite Archie's insistence. When Ainz' summons Archie, Shalltear and her vampire brides are in a rush to dress her as she does not have any clothing. When Ainz sees Archie again she crawls to Shalltear who uses her as a footrest while Archie licks Shalltear's fingers. Ainz requests that Shalltear instruct him for an upcoming ball; in return Archie asks for Shalltear to take her chastity as her reward.

(Web novel said she was eager and did things with a smile so this is probably an "early depiction". There's more to that picture if you want to reverse image search for the source.)

Eventually she helps Ainz with the ball and gets to live in the tomb with her sisters, Ainz noting that her sisters make good hostages in case he needs her experience as a noble in the future.

Bibliography, a translated archive of all mentions of Archie in the web novel: https://archive.org/stream/manga_Overlord/%21Side%20Stories/Overlord%20-%20Volume%2007%20-%20Webnovel%20Ending%20%2B%20Other%20Web%20Novel%20Chapters_djvu.txt