Sweet Little Serena (Rewrite)

The greatest Shadowhunter of his generation is what they say about the legendary Jace Wayland. But, what you don't know, is that they also say the same of his twin sister, Serena. For Serena is many things. She is the Clave Envoy to Downworlders. She is the parabatai to Isabelle Lightwood. And Serena herself, is a Lightwood, because she's married to none other than Alec Lightwood.
Having grown up together, the four of them made a promise that whenever they go on a mission, four go in and four come out.
Join them as they fight to keep that promise when their world is turned upside down by the introduction of Clary Fairchild, the fiery daughter of the biggest threat to the Shadow World, Valentine Morgenstern.
Will they stay together? And above all, will they stay alive?

(Seasons 1-3)
(A/N: This is the rewritten version of the original story already published. It is also available on AO3. Would like to note that I have nothing against Alec being gay or Malec, I love them, this was just an idea that popped into my head, so please don't hate. Please don't plagiarise any of it.)
(Disclaimer: I don't own anything except Serena and any original scenes and dialogue that I have written.)