Ok so now ima be crossing some animes into the mix.
Soul eater– So when they tried to tell the others about their world they assumed it had no magic. They told them 'we don't have magic like this back home' they never out right said we have none. When their demons where incontrol they taught them about the witches from this world. They didn't eminently think all witches are bad like they are taught because in their world because a witch was related to them.(aunt P magic is weird and no the twins cant use that kind of witch magic from their world, they are just resistant to it.)
I'm not sure if they would be misters, weapons, or a mixture of both. If they were both Ritchie and Brandon could still turn fully into weapons however that puts a strain on their bodies, the strain is lessened when they are the ones welding eachother. Ritchie has black blood in him, I don't know how it got there yet.
Why Ritchie and not Brandon? Its because Rian is more mature than Brandeen and Brandon is more mature than Ritchie, with this logic it would make sense for Ritchie also to be insane because of something. Ritchie will be fine as long as he doesn't purposely give into the black blood or Brandeen doesn't use his insanity magic on him. Although Ritchie would be a good counter because Brandeen can't make him kill his self. They haven't tried to used deaths call because they'd figure it wouldn't work.
*I could just imagine them all (All the guilds) playing a game and one person was like twins try calling death, thinking it would be at Michael or Lo'pho. So they went to the mirror, said the chant, and knocked. To everyone's surprise he answered, though the reception was weird and the image would glitche out*
D.gray man– They both either hold innocents or are members of the Noah family that hasn't awakened. If they are Noah's if they awaken they will still act like their old selves and despises the rest of the family. They would also be best friends with the heart. They hate akumas and wish they were never made. They heart is what helped send them to fto. The demons and Michael are able to tell a part of the twins souls lay dormant, but they also don't want to wake it up. They sensed 'evil's from it.
If they were exorcist they hated the foundation and ran away and is still on the run. The foundation treated them poorly especially sense they have the blessing of the heart(made that up), meaning they have the firepower closest to the heart without being it. The heart was one thing that sent them here. She did have help from the other world, she sensed something happening that would help send them some were 'safe', at least safer from the people torturing, experimenting, and overworking them. They still have their innocent, but it lays dormant.
I'm not sure what type they have( Equipment, Crystal, Parasitic). They would have to get both their demons and innocents to like eachother, so none out of the three of them gets hurt.
Fma/Fmab– Ok Ritchie is going to be kinda like Ed. Unlike Ed, Ritchie was forced to see the truth twice in a row. The twins father was a horrible man that treated them and their older sister poorly. The mother was sick and dying, so she couldn't do anything. Their sister was used as income.
Anyways when Ritchie was like 5 his mother died a year ago and sister was beaten half to death. The father gathered materials to bring the mother back to life, before he could do that he had Ritchie combined his sister and a dog together to save her life. What they didn't know was Dad had the mothers soul bound to a box.
How he did this with little to no consequences by using a philosophers stone. He had blood from all the siblings, the corpse of his wife, things that makes up the human body, the stone, and the box with her soul in it. He had both Ritchie and Brandon transmuted this. That night Ritchie last an arm and leg, Brandon lost an eye.
The father thought the transmutation didn't work because of the mess of flesh that was his wife. We was going to hit them for messing it up when the sister attacked him. When she killed him she gently grabbed Ritchie and Brandon and took them to a hospital.
Ritchie was forced into the military because he committed 2 crimes, very smart/inventive, and how good he was at transmutation. He went with little to no fight because they promised not to have his brother join and let the sister go into hiding. Brandon still followed him almost everywhere.
He was in the war and killed people. The reason I had the mothers be different from the other humongous(?) was because she wants her son to kill her. She vaguely remembers them and see feels protective of them. She would still kill others, but not them. She also wanted to be free from this curse and father. Father had a big grip on her, so she couldn't tell them about his plains.
When she found out Greed met and became friemys with them, she bugged him to look over them, he agreed.
Now just like the anime they both defend father. Both Ritchie and Brandon sacrificed their Alchemy to fix everything that has happened in the fight and their bodies. Greed survived and pestered them.
Ritchie was referred to as the 'Mechanical State Alchemist' because of his ability to create things.
Mrs.P is the only one to fully know the twins past. She is this world's vision of their aunt. Her magic connects fto and Salode her by memory, even though salode her was a ghost watching over the twins.
Their alchemy can return if Truth needs a favor and they do it, they can keep it or if they get deaged.
Greed and the sister are still alive. Use that knowledge to your advantage.
(Made June 3,2020. Sorry if there are any mistakes.)
