A while ago I read a manga and now I can't remember the name. It was about a girl who became like a mother for her brothers after their mom died. The whole family then dies in a fire and the girl is reincarnated in a world with magic, but because she was such a good caretaker for her family she becomes a maid for an old couple. She then finds out the old couple are the old king and queen, then they move back to the palace and she then becomes a maid for the new king.
Later in the story she meets a man called god of death (or something similar) who turns out to be her brother. Even later in the story she finds her other brother who also reincarnated as a great sage.