Board Thread:Skyrim/@comment-10207438-20130919024334/@comment-217.22.43.95-20140223233640

Lydia is a Houseclarl, one who devotes her life to protect Jarl Balgruf, (kinda like a brother of the nights watch form GOT). So if she had not been given to the dragonborn she wold have no chioce but to follow the order of Jarl Balgruf. As she was given to the Dragonborn she will follow him and do his every order even if means her death. Her only loyalty is her master.