So like… Does Custas know about Tartah’s silverwash?
I’ve seen a lot of people across different platforms make the assumption that he does, seeing as the two canonically spent a lot of time together back in Kalhan studying apothecary, but after rereading a lot of their scenes together across the Silver Eve arc, I don’t think Custas knows about Tartah’s condition, or at the very least he doesn’t know how it’s impacted Tartah’s life and his place in witch society.
For most of the time we know him, Custas has the “witches can have/do anything because they have magic” mentality that most outsiders seem to possess, which shapes his relationships with both Coco and Tartah from as early as chapter 43. He believes that their lives must be easy because they have magic, and that they don’t need to struggle to have a place in society like he does. Ironically, the two witches he displays this sentiment towards are probably the two who fit this idea the least within the current story.
For Coco, we know she wasn’t born with the privileged life of a witch like Custas assumes. We can see her struggle with this throughout the early Silve Eve arc. She cannot tell him the truth about her being born an outsider without exposing the secret of magic, but she cannot keep her past a secret without feeling hypocritical.
With Tartah, this juxtaposition between how he’s perceived as a witch by Custas and his actual relationship with witch society is perhaps a bit more subtle, as these moments rarely cut to Tartah looking horrified the same way Coco does. Unlike Coco, Tartah was born into the privileged life of a witch as Custas says, yet he’s also someone who distinctly sits outside of both witch society at large and the outsiders. His silverwash means that most adult witches will never view him as a “real” witch due to his inabilities, but his status of being from a witch family means he’ll never be an outsider to the world of magic. He’s in a limbo, too much of a witch to be an outsider, not enough of a witch to be “normal”
You’d think, if Custas was aware of this distinction between Tartah and “normal” witches to some degree, it would have some up at some point between his claim in chapter 43 and his apology in chapter 45—but it doesn’t. Custas remains as unaware of Tartah’s social outsiderness as he does Coco’s literal outsiderness.
While this could all just be interpreted as Custas knowing about Tartah’s disability but not the effects it has on a witch, I’d like to bring up his reunion with Tartah and Coco in chapter 51. After becoming a brimmed cap and realizing that there were solutions for fixing his legs with magic, Custas is angry at how his supposed friends were “keeping” the fact that they could have healed his legs from him. It stuck out to me even on my first reading of this scene that Custas never once mentioned that Tartah ALSO has a disability that could have potentially been fixed with magic, because this fact would contradict his argument.
If Custas were to acknowledge the fact that Tartah explicitly pushed the narrative that magic cannot heal people while also being disabled and having access to magic, his argument that Coco and Tartah were keeping this magic away from him solely because he’s an outsider would fall apart. If Tartah is both a witch and someone who suffers from a disability, why wouldn’t they use magic to fix it? Custas can’t maintain his argument without acknowledging Tartah’s silverwash, but since he doesn’t, it’s more likely that he just doesn’t know about it at all.
I also don’t think that silverwash in general is common among outsiders, or at least not to the level it is in witch societies. Coco needed Qifrey to explain it to her, and Tartah’s first mention of it towards the end of chapter 13 is very offhanded, like he assumed that Coco already knew what it was. This would line up with him not realizing she was originally an outsider until later in chapter 16.
TLDR; I don’t think Custas knows about Tartah having silverwash based on his interactions and dialogue from chapters 43 & 51, and I don’t think silverwash in general is a common or known condition among non-witches.