D: [dice] x 10 minutes

You command blood to serve you. As you cast this spell, make a melee attack with a dagger against a blooded target. You have a [sum] bonus to your attack roll and a bonus of [dice] to your damage.

You create a Blood Elemental with as many hit points as the damage you inflicted (it counts has having [dice] HD). It will obey your command.

If you invest 4 [dice] or more into this spell, the elemental permanently becomes one of your followers.

blood + thrall

From Unlawful Games’s Blood Aspirant