There are many things that you can be faithful to, not all of them of honourable. Fidelity as used here refers to being faithful or loyal to God, to yourself and your beliefs, to your family, and to your friends.
This is not the same thing as seeking revenge. There is a difference in revenge and in fulfilling an obligation to your loved ones.
All others are mere acquaintances.
I am the true warrior, so the true warrior is also a true friend once that bond has been entered into.
He will take his fidelity to his friends and family seriously, as he does his spiritual relationship with his God.