Actions

Extra Attack Brolof attacks twice with his Guardian poleaxe (+1) or an equivalent attack, and once with his hafted strike if he has a Bonus Action.
Guardian poleaxe (+1) - Lightning charge (3/day) Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 1d10+6 piercing or slashing damage plus 1d6 lightning damage. In addition, Brolof can invoke his Fire Rune to deal an additional 2d6 fire damage and it must succeed a Strength Saving Throw DC 15 or be Restrained for 1 minute. While restrained, the target takes 2d6 fire damage at the start of each of its turns. The target can repeat the Saving Throw at the end of each of its turns, ending the effect on a success. Furthermore, Brolof can use a Bonus Action to force the target to succeed a DC 17 Strength Saving Throw or it is knocked Prone.
Hafted Strike (Bonus Action) Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 1d8+5 bludgeoning damage.

Reactions

Runic Shield (4/day) When another creature is hit by an Attack Roll within 60 ft. of Brolof, he can force the attacker to reroll the d20 and use the new roll.
Stone Rune (1/rest) When a creature ends its turn within 30 ft. of Brolof, he can use his reaction to make the creature succeed a Wisdom DC 15 Saving Throw or be Charmed for 1 minute. While charmed this way, the creature has a speed of 0 ft. and is Incapacitated, descending into a dreamy stupor. The creature repeats the Saving Throw at the end of each of its turns, ending the effect on a success.
Polearm Master Brolof can make attacks of Opportunity when creatures enter his reach. If he also didn't move last turn, he can use his Guard weapon trait to deal no damage but decrease the target's speed to 0 ft. until the end of its turn.