Blood Oath

When  you cast Blood Oath, you swear to achieve a difficult, task.  Typical tasks are to protect someone/thing, deliver justice/vengeance upon some perpetrator, or to destroy a powerful magic item, but others may be taken at the DM's discretion.

Once you swear the Blood Oath, you gain the following penalties:

-1 to any skill check if is not in pursuit of the oath and take 2d10 damage every 12 hours if you make no attempt to satisfy the Blood Oath.

You also gain the following bonuses while attempting to satisfy the Blood Oath:

a) +1 to any skill (including passive skill checks)

b)  +1 to damage (not to hit) versus any creature that opposes your attempt to satisfy the Blood Oath.  (i.e. if you sweat to kill Saul, you get +1 damage against Saul and anyone working for Saul, but not against random monsters)

c) If you are killed before satisfying your Blood Oath, you become Undead, usually a Revenant (but not always - DM's Choice), that is sworn to fulfill your Blood Oath.

The Material component is considered cursed after this spell is used.  This spell is instant on you, but if someone cast's a Remove Curse, Greater Restoration or Wish on the Material Component, it ends the spell.  The spell continues even if the Material component is turned to dust (the dust is still cursed).  If you complete the Blood Oath, the curse is lifted, the spell ends, and the material component is destroyed  (but some blood oaths can never be completed, such as 'defend the keep').

Note, while this spell us cast-able by Paladins, not all Paladins consider it appropriate.  Consulate your God for further information.