Oswald wasn't interested in Sofia in the slightest. He flat out literally told her he just wanted to be friends when she asked. Oswald hasn't shown the slightest romantic inclination towards women ever. That's why she took on a more maternal role for him and began to act in that way. LMAO thinking Oswald doesn't still care about Ed in s4, the mix of scared and longing on his face when Ed caresses him, and for that matter Ed just using Oswald has to involve him gently caressing his face like that, sure. For that matter the brokenness and concern and worry Oswald had when he said what he did to Lee when waiting for Ed to come back.

They were just using each other, don't care about each other? Give me a break Oswald trusted Ed to save MARTIN whom Oswald had come to deeply care about. Ed endured torture and wouldn't give up Oswald to Sophia. Oswald gave up his revenge for Ed. People forgetting that whole thing with the dentist and the torture and the dentist saying he wouldn't give you up, and Oswald then giving up his revenge on Sofia? Then Oswald tells Ed he trusts him and he means it. Also the deal with Oswald voluntary letting himself get frozen -knowing- what that did to Ed? Ed acknowledged that it, appreciate it, and was impressed "Well, well" Oswald.

"Riddler" used Ed to get out of Arkham, ok but you're forgetting Ed was going to KILL himself, he was in a very dark place, and he was crying out for need, for help. Who does he go to when he's in that darkest of places? Not Lee, not Grundy, not anyone nearby in the Narrows, no he goes all the way to Arkham to the Narrows. Oswald is the one person who can set him free, he saved him.