Cerulean Convocation

Holding your hand in the air you invoke the Cerulean Sign, using its nature you gather energy from any willing creature(including yourself) within range, converting this energy into a rending force.

While concentrating on this spell, any willing creature may use their bonus action to gift 1 Hit Die(per round) to the attack damage. They may gift as many hit dice as they have available to them. Once gifted these Hit Dice are spent and cannot be regained for 1d4 days, even if concentration drops or the spell fails.

The damage for this spell starts at 2d10 Radiant Damage. For every round of combat this spell is active, add 1d10 additional damage.

The Convoked energy energy can be directed to any point with 150 feet, each creature in a 40 foot radius sphere centered on that point make a Dexterity saving throw. A target takes the accumulated damage on a failed save, or half as much damage on a successful one. Aberrations and Monstrosities originating from the Far Realm are vulnerable to this damage.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d10 for each slot level above 5th.