I pick up a lot of headcanons or ideas/interpretations for charcaters while I write. Oswald, as you can probably guess, if my favourite character, and the main character I write. So here we go:

Headcanons

•Gay
•His mother only spoke to him in Hungarian when he was a baby so it became his mother tongue. Before he started school she started to teach him English, but he fell behind from the langauge barrier and differences. He is a second generation immagrant, so she wanted to keep her culture alive.
•But he is a fast learner
•He taught himself to speak English, and forced himself to adopt an american accent. It's been so long he doesn't actually know what his natural accent was.
•Changed his name to Cobblepot at 8. Gertrud was too stubborn and proud of her name to americanise it when he was born.
•Loves birds. He owned a cockatiel called Lajos, which was lost when he flew out the window. Would feed birds and gain items from them in return.
•Suffers from nightmares. He will usually have them, at least once a week. It's more than that if he's going through something distressing. (His mother dying caused nightmares for weeks. Nightmares from Arkham were there for longer)
•Sleep talks. He talks in his sleep and usually slipping into Hungarian
•Skilled at piano. His mother taught him to play.
•Had a crush on Jim for a while but soon realised Jim didn't like him at all and was using him. He stayed hoping they were friends after the feelings went away
•Something else happened to him in Arkham (s4) that the writers never showed, and Oswald never told anyone
•Adopts Martin

-Other headcanons I support but don't use all the time

●Trans
-Deadname is Ilka
-Gertrud suggested Oswald as a name, as that's what she would've called him, and he liked it so it stuck. He also accepted the name because it's who he would've been if he was born male, and took it with pride because his mother named him.
-Fish figured it out, but she helped him present more maculine and gave him advice.

•Asexual
-I don't use it, as my ideas of Oswald doesn't fit, but I do agree it fits Oswald really well. Especially after Robin said that Oswald's attraction to Ed probably wasn't sexual, but romantic.

Interpretations

•He is very insecure about himself. From a life of bullying and belittling, he just wants people to love him. But it doesn't come across like that. (Definitely see this in season 3 and 5). He doesn't really understand how to express love, especially since, although he loved his mother, ahe could be smothering.

•Definitely impulsive, especially when angry. But mostly a calculator, and a planner.

•He acts out in harmful ways out of fear of abandonment to try and stop people from leaving him (Such as Ed). It can come across as possesive some times, but he's desperate to keep them that he doesn't think of how it may effect them. -He has bad abandonment issues.

•He blames himself for his mother's death. The "therapy" dream in Arkham symbolises that he felt helpless to save her (tied to a chair gagged), and thinks it's his fault (watching himself kill her). - Already posted an analysis on this.

•He still admired and loved Fish, even when he took her down. Thats why he kept trying to reach out to her, and that's why he toasted her with Butch. In s3 he was still nervous that she had changed her mind about not killing him, but he was glad to have a mentor once he realised she wanted an alliance.

•Absolutely never stopped loving Ed. - Ed tells him love is about sacrifice, and since that episode Oswald gave up so much for him that he would've never given up for anyone else (revenge on Sofia, his eye). He keeps telling him that he'll kill him, but he never even attempts it. The look in his eyes when they hug in season 5 was full of relief and sadness.

•He's not much scared of other people, mainly his opponents. But he's terrified of Jerome. Maybe it's because Jerome is chaotic and mad, so you never know what he may do or how far he'd go, but Jerome seemed to be the only person that truely scared Oswald.

•Not really an interpretation, but I (and many others) feel like something else happened in Arkham with Jerome. Yes the constant threats and Jerome's general madness probably scared him, but it's possible Jerome hurt him off screen that made Oswald scared as hell. Especially since you see him mostly compliant and playing along with Jerome once he was out, but he went to Jim for help. Also you might see it in scene where Os is writing the letter and Jerome leans over his shoulder to talk into his ear (eg. Oswald's reaction) can be interpreted depending on how you feel about this. Which I said in the last point, but Oswald doesn't seem to scare easy by his opponents,  so why was Jerome so much different? Just a thought.