Someone who's leal is devoted and dependable. Your most leal pal in the whole world is your closest, most trusted friend.
The adjective leal is so old fashioned that not many people use it these days, but if you want an unusual way to describe someone who's steadfast and loyal, leal is perfect. You might talk about your leal dog, for example, who stays close by even when he's not on a leash. Leal is a Scottish word, originally spelled lele, from Middle English and dating from about 1300. For centuries, it filled in for for the word loyal in Scotland.