Shilgengar, Sire of Famine

Finality counters work on any permanent, not only creatures. If a permanent with a finality counter on it would go to a graveyard from the battlefield, exile it instead.

Finality counters don't stop permanents from going to zones other than the graveyard from the battlefield. For example, if a permanent with a finality counter on it would be put into its owner's hand from the battlefield, it does so normally.

If you sacrificed an Angel to pay the cost of Shilgengar's second ability, use the toughness of that Angel as it last existed on the battlefield to determine how many Blood tokens to create.

Finality counters aren't keyword counters, and a finality counter doesn't give any abilities to the permanent it's on. If that permanent loses its abilities and then would go to a graveyard, it will still be exiled instead.