Diferent of Mikasa she was haised and brainwashed to be a bodyguard and she believes Noah is the master she chose, a genius who is kind and a good leader who always had a important hole in the word, not only that but he the only resemblance of a family to her both her support/savior and someone she must protect, a family who mind you was always sick and on the verge of dying by reasons she can't control so I think it all only reforced to her that she needs to save him when she can, and the way she was trained to do,
the be fair I don't think she would have to sacrifice herself if Noah was not the first to jump to danger and sacrifice himself for strangers
Lol i dunno but I dont like that Li (bodyguard/maid) girl and her Mikasa-like attitude. I'm not saying I hate Mikasa of AOT but I dont like attitude like that. Can't u at least trust Noah and stop that unnecessary sacrifice thingy like that lol. I hope there's no romance or whatsver between her and Noah... I just want him to be with his family excluding the wife lol