ok i want to talk a little bit about Cassandra Clare and the use of incest as a plot device because i always see stuff, mostly on tik tok, talking about how CC keeps continuously writing incest into her stories and about how weird it is. but the thing is, she only ever writes it to depict how thoroughly the adults in these kids lives abuse and manipulate their kids. 

like in tmi with jace, sebastian, and valentine: valentine told jace that him and clary were siblings because valentine saw that for once in jaces life, jace might choose someone over him. so he lied and said jace has demon blood and was clary’s brother so that jace would think that he was dirty and vile and disgusting and wrong. that clary was good and pure and angelic and jace was evil and demonic, because how could he be anything else when he was in love with his sister, so he might as well join up with valentine. with sebastian, sebastian was so desperate for his fathers love and approval that even after valentine died, he wanted his love so he tried so hard to be like jace. he thought that loving clary would be the thing to fix him, because it was the thing that “fixed” jace. and jace had their fathers love. so did sebastian really have feelings for clary? probably not. but he couldn’t see any other difference between him and jace and how they were brought up other than jaces love for clary, so why wouldn’t he try loving clary too?

in tlh with grace, jesse, and tatiana: tatiana only ever viewed grace as a possession not a daughter, shown through the fact that she continuously used grace to further her own agenda and disregarded any and everything grace ever really cared about, including graces familial relationship with jesse. tatiana was willing to marry grace off to jesse the moment it suited her, regardless of the fact that grace always viewed both tatiana and jesse as family. because tatiana never viewed grace as family. grace was only every a possession, and tatiana bought and used her like one.

none of these depictions of incest are actually romantic. CC is not saying “oh haha brother/sister relationships so sexy” she’s using it to show just how terrible and fucked up these parents are that they would use their children and make them feel like shit in this way. she uses it to show abuse and manipulation and evilness, not to promote sibling fucking.