i was just thinking about my version of Steppenwolf and Menniker’s relationship, along with their Anti versions, which I call Stephen and Michael. You can read it under the thing here.
Canon/mixed with my version: Menniker and Steppenwolf were close as children and even with Steppenwolf suffering with issues like losing his father, bullying and isolation at school and depression in general, Menniker always cheered him up and helped him. When they got older an incident happened with Menniker's father and his dark 'spirit' possessed him and made him do bad things. When confronting him, Steppenwolf could sense it and knew it wasn't his cousin but he couldn't let him get away with his crimes and deeds, so he sent him away and banished him to the Twilight Cage/Zone with his chaos energy, even tough he felt miserable doing so and missed him. They do wound up reuniting many years later. (Different for each of them because time slows down in the cage)
Anti version: Michael (Anti-Menniker) always knew something wasn't right with his cousin, Stephen (Anti-Steppenwolf), Stephen very strange behaviour, seeming very emotionless and aloof and just very... off, like most of his family (except Stephen's father who saw nothing wrong with him and was fine with his behaviour), tried to help him and make him happy and all of that.. but never could. Sometimes it would make Micheal depressed and useless but Stephen would always tell him not to, because it wasn't something they would try to fix and he knew he was broken, he just didn't care. Sometimes as he got older he would pretend to function properly, but Michael always felt he was pretending on the inside.
As they grew older, they started to split apart, more so Stephen. While Michael became an officer of the law and even got to become a captain/lead detective whatever, you know what I mean, Stephen started doing horrific crimes yet with no remorse, shame, guilt or even any reason, sometimes he just did them with no explanation. Michael had to hunt him down and wanted to just arrest him but his superiors said he needed to be killed, as he had done too much. He was extremely reluctant to do it but knew he must.
He eventually found a hide-out and was on his way to sneak in and shoot him while he was sleeping, even though he felt himself truly not wanting to do it. Before he could do it, Stephen woke up and... acted happy to see him, saying it's been so long since they've seen each other and he missed him and cared about him so much... this caused Michael who was gripping the gun with a shaking hand behind him to start tearing up and close his eyes, saying he couldn't do it.
But then he found himself quickly stabbed by his cousin, saying in a very emotionless voice that not even he was going to get in his way for what he's looking for, which he felt was this path.
He simply said goodbye to his cousin as he walked out while he died, his body being found sometime later by the rest of the force.(edited)