Akh'lut

Keen Hearing. The akh'lut has advantage on all Wisdom (Perception) checks that rely on hearing.

Underwater Predator. The akh'lut has advantage on all attack rolls whilst in water.

Multiattack. The akh'lut uses its Primal Bellow. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit:  22 (3d10 + 6) piercing damage plus 5 (1d10) cold damage.

Claw. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 12 (2d6 + 5) slashing damage.

Tail. Melee Weapon Attack: +10 to hit, reach 18 ft., one target. Hit: 15 (2d8 + 4) bludgeoning damage. Note: this attack only effects creatures behind or below the akh'lut.

Frost Breath (Recharge 3-4). The akh'lut exhales, shooting a blast of freezing air out of its maw. The air freezes anything it touches in a 45-foot radius of the akh'lut's head. Each creature in that area must make a DC 15 Strength saving throw; if they fail, they take 1d12 + 5 cold damage. Damage can be reduced (1d8) by using a fire spell; Fire Shield negates all cold damage.

Primal Bellow. The akh'lut lets loose a deafening bellow. Each creature within 100 feet of the akh'lut must succeed on a DC 16 saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the akh'lut's Primal Bellow for the next 24 hours.

Saving Dive (only in deep water, 5/day). If the akh'lut fails a saving throw, it can dive underwater, out of harms way. Make a Constitution saving throw (DC 12); if it succeeds, it resurfaces, joining the fight again; if it fails, it vanishes and the encounter ends.

The akh'lut can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The akh'lut regains spent legendary actions at the start of its turn.

Detect. The akh'lut makes a Wisdom (Perception) check.

Claw. The akh'lut makes a claw attack.

Huge Wave (Costs 2 Actions, only effective in deep water). The akh'lut whips up an enormous wave with its tail. Each creature within 90 feet of the akh'lut must succeed on a DC 18 Constitution saving throw or be stunned. All ships and boats within 90 feet take 16 (2d8 + 4) bludgeoning damage.

Ram (Costs 2 Actions, only effective in deep water). The akh'lut powers through the water, knocking everything in its path aside. Each creature in its path takes 12 (2d6 + 4) bludgeoning damage and must succeed on a DC 15 Strength saving throw or be knocked unconscious. Each . Note: this action only affects creatures and vehicles in front of or above the akh'lut and can only be used immediately after succeeding on its Saving Dive.