When a creature within 10 feet of the sentinel that isn’t an undead or a construct takes piercing or slashing damage, it must succeed on a DC 15 Constitution saving throw or take an extra 7 (2d6) damage of that type. The sentinel’s Blood Reservoir increases by an amount equal to the extra damage dealt.

The bloodstone sentinel absorbs blood that is spilled nearby into itself. This reservoir of blood grows when a creature takes extra damage from the sentinel’s Blood Lure trait. The Blood Reservoir can’t exceed the sentinel’s hp maximum. As a bonus action, the sentinel can reduce the Blood Reservoir by 10 to cause one of the following effects:

• Empower Blood. A friendly creature within 30 feet of the sentinel that isn’t an undead or a construct has advantage on its next weapon attack roll.

• Inspire Fury. A creature of the sentinel’s choice within 30 feet of the sentinel must succeed on a DC 15 Charisma saving throw or immediately use its reaction to move up to its speed and make one melee weapon attack against its nearest ally. If no ally is near enough to move to and attack, the target attacks the nearest creature that isn’t the bloodstone sentinel. If no creature other than the sentinel is near enough to move to and attack, the target stalks off in a random direction, seeking a target for its fury.

• Sustain. A nonhostile undead creature within 30 feet of the sentinel that must eat or drink, such as a ghoul or vampire, regains 10 hit points.