What is the relationship between Wolverine and Sabretooth?

Victor Creed, also known as Sabretooth, is an animalistic mutant who possesses superhuman strength, mobility and cat-like claws and teeth. He is Wolverine’s half-brother.

Why can’t Sabertooth have adamantium?

16 SABRETOOTH: BIGGER AND STRONGER One of the primary reasons Sabretooth didn’t initially get an adamantium skeleton when Logan received it was because he was big and strong enough without it, and him having it would make him nearly unbeatable. It was one of the only edges Wolverine had over his bigger nemesis.