Upper. When Grendel would take lightning damage, his Overpower immediately recharges.   Lightning Absorption. Whenever Grendel is subjected to lightning damage, he takes no damage and instead regains a number of hit points equal to the lightning damage dealt.   Pack Tactics. Grendel has advantage on attack rolls if at least one ally is within 5 feet of the creature he's attacking and the ally doesn't have the incapacitated condition.   Brute. A melee weapon deals one extra die of its damage when Grendel hits with it (included in the attack).   Charge. If the Grendel moves at least 10 feet straight toward a target and then hits it with a melee attack on the same turn, the target takes an extra 11 (2d10) damage. If the target is a creature, it must succeed on a DC 17 Strength saving throw or be pushed up to 10 feet away and knocked prone.