Sense lifeblood

2nd-level divination (sangromancy)
Casting Time: 1 bonus action
Range: Self
Components: S
Duration: Concentration, up to 1 minute
As part of casting this spell, you must expend two hit dice or the spell automatically fails. If you do, you can sense the lifeblood flowing within creatures you can see. For the duration of the spell, you can sense whether and how two or more creatures you can see are related biologically.
In addition, you know whether the creature’s current hit points are equal to or below half their maximum hit points and, when you deal damage to such a creature, you roll two additional dice to deal bonus damage. The dice rolled to determine this bonus damage are the same as the two you expended to cast this spell.
At Higher Levels. When you cast this spell with a 4th or 5th level spell slot, you can maintain concentration on this spell for up to 1 hour. When you cast this spell with a 6th level or higher spell slot, you can maintain concentration on this spell for up to 8 hours.