Hah well I can say Siren is more text than SPN will ever be, at least. I'm not in the fandom but I have seen some reviews that already talk about the queer content as canon, which I guess it ~is~ but I'm still wary to see where they go with it because they can still walk it back to fanservice or a misunderstanding.

By the way I just realized that there may be more one show with a title like Siren, so if this is the drama-fantasy-horror show featuring a mermaid, then I'm talking about that one!

The main characters are Ben and Maddie, a human couple in an established relationship, and Ryn, the mermaid. Ben and Ryn connect early on in way that makes it seem like it's leading to a love triangle, but the usual jealousy tropes don't kick in, and instead Ryn grows attached to Maddie as well, and at one point kisses her. There's some very obvious poly imagery, with Ryn inserting herself into Ben and Maddie's relationship, buuuuut I feel the show is more explicit about Ben's attraction to Ryn while the Maddie/Ryn feels more one-sided, plus Ryn has a non-human understanding of intimacy. So I'm still kind of holding my breath where they're going to go with it in season 2.