Despair's Osseous Smite

Despair gains the ability to smite with bone shards on 1 strike with an Action.
The target hit by the strike takes an extra 2d4 Necrotic damage from the attack. Until the spell ends, the target is marked with Despair's Blood magic Bright Light in a 5-foot radius, attack rolls against it have Advantage, and it can’t benefit from the Invisible condition.

The damage increases becomes 4d4 at level 5
The damage increases becomes 6d4 at level 7
The damage increases becomes 8d4 at level 11

This can be casted only once per round.