Covenant of Blood

If the target permanent or player is an illegal target when Covenant of Blood tries to resolve, it won't resolve and none of its effects will happen. You won't gain any life. (Any creatures you tapped to cast Covenant of Blood remain tapped.)

2014-07-18

When calculating a spell's total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell. Convoke applies after the total cost is calculated. Convoke doesn't change a spell's mana cost or mana value.

2024-01-12

Because convoke isn't an alternative cost, it can be used in conjunction with alternative costs.

2024-01-12

If a creature you control has a mana ability with in the cost, activating that ability while casting a spell with convoke will result in the creature being tapped before you pay the spell's costs. You won't be able to tap it again for convoke. Similarly, if you sacrifice a creature to activate a mana ability while casting a spell with convoke, that creature won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for convoke.

2024-01-12