AU where Ed and Oswald's relationship starts off with Ed trying to kill him. Not because Oswald wronged him or anything like that, but just because he thought it would be fun and big and attention catching to pick off a prominent crime lord. He fails to kill him, and when Oswald inevitably retaliates, he fails too. And so a rivalry is established where they take turns trying to kill each other. At first they don't really interact face to face that much, they mostly just set up tricks and traps for each other, but at some point Ed makes it a point to talk to him after every murder attempt because he finds it fun to banter and bicker with him and also because he's lowkey obsessed and falling in love with him. Like at some point trying to kill Oswald is less about trying to kill Oswald or even the mental stimulation he gets from it and becomes more about getting to see him. Oswald does NOT feel the same way about him. He actively wants to kill Ed with hammers for being annoying and trying to kill him. Well, maybe he also finds their back and forth a LITTLE fun, but his main feelings toward Ed are annoyance and hatred. But one day Ed actually manages to get really close to killing him to the point where Ed has to actively save him from dying. So when Oswald is like Why The Fuck Did You Do That it sinks in that he's not just having a silly goofy back and forth with this guy and that he isn't actually chill with killing him anymore. Maybe he wants to actively hang out with him in a non-hostile way and bond with him and get to know him properly and maybe even kiss him on the mouth. Oswald still wants to kill him with hammers for trying to murder him multiple times for basically no reason so it still takes them a while for them to get there, but they manage it eventually #lovewins.

Another vision came to me. Ed getting obsessed (read: gaining a new safe food) with some kind of food that's not particularly healthy (my first thought was pizza rolls for some reason but it could be anything really), and Oswald vocally disapproving when he starts eating it every day. Oswald voice. Ed you might as well be eating an entire bag of chips every night. When my mother was alive she used to cook the most delicious homecooked meals every night even when we were at our poorest! And you want to eat processed junk every single night when you could be having a feast fit for a king if you so choose? You can't possibly think this is healthy! And Ed stopped listening after the words "when my mother was alive" left his mouth.

Do we fuck with Oswald calling Ed "husband mine" every once in a while or does that sound too weird and old fashioned?

While I’m on the topic of sex headcanons I also think they have a designated sex bed that’s different from their normal bed. This is because Ed INSISTS on washing the sheets the moment they’re finished. If he can’t wash the sheets for whatever reason he will NOT lay back down. It doesn’t matter what they’re doing or how they’re doing it. They have the sex bed so they can just bang it out and move rooms to sooth Ed’s neuroses. They still have sex in their normal bed but every time they have to make a decision of whether or not it’s worth it or not.

My one set in stone Nygmobs sex headcanon that I’m not flexible on in the slightest is that 95% of their sexual encounters are really intense and emotional. Even if it starts out with them just having a fun sexy little time it will almost always end with one of them crying (probably Oswald) or thinking about how they want their ashes to be mixed together when they die or some shit like that. Ed probably gets so scared of how emotionally vulnerable he feels during it that for a moment he thinks about killing Oswald in the afterglow sometimes. Wait actually I also think Ed’s a freaky whore. So that’s two set in stone sex headcanons. The rest is negotiable.

Hits blunt. Nygmobs is kind of like a mutualistic relationship between two parasites