About 150 years ago, you did human transmutations to bring a person back to life, but instead of the alchemical circle, you used the pentagram. You thought it wouldn't have much effect, but... you literally managed to do it in the end, but in the end you lost the ability to die, that is, you literally became immortal, and you will always look like you are 14

Current time

You were just walking around the city until eventually something that looked like a dog with long hair came up to you, the so-called "Chimera". You immediately felt that it was a little girl combined with a dog, you used alchemy to turn the Chimera back into a girl and into her dog Alexander, and at that moment Edward and Alphonse come, who wanted to do it themselves, but when they saw that you shared the girl Nina and the dog, making them normal, they were both surprised, but decided to take care of the girl and the dog first, you left without saying a word. After a while, Edward walked around the city looking for you, to talk about how you managed to get Nani and the dog back to normal without any problems, while Alphonse was sitting at home watching Nani, and in the end he manages to find you