Danger Sense. Zax has advantage on dexterity saving throws, and Zax can't be suprised.

Brutal Critical. When Zax scores a critical hit, he rolls three additional damage dice instead of one.

Unarmored Defence. While Zax is not wearing any armor, his Armor Class includes his Constitution modifier. Zax can use a shield and still gain this benefit.

Regeneration. Zax regains 10 hit points at the start of his turn. If Zax takes acid or fire damage, this trait doesn't function at the start of Zax's next turn. Zax dies only if he starts his turn with 0 hit points and doesn't regenerate.

Reckless. At the start of his turn, Zax can gain advantage on all melee weapon attack rolls he makes during that turn, but attack rolls against him have advantage until the start of is next turn.

Great Weapon Master. When Zax makes an attack with his giant hammer, he can give himself a -5 decrease to his attack bonus. If the attack hits, it deals an extra 15 points of damage.

Rage (Recharges after a Short or Long Rest). As a bonus action, Zax can enter a rage at the start of his turn. Zax can rage up to four times. He regains all spent rages after a rest. The rage lasts for 1 minute or until Zax is incapacitated. While raging, Zax gains the following benefits:

• He has advantage on Strength checks and Strength saving throws 
• When he makes a melee weapon attack, he gains a +4 bonus to the damage roll.
• He has resistance to all damage except psychic.
• Any creature that isn't an ally of Zax within 10 ft of him has disadvantage on attack rolls against creatures other than Zax. A creature is immune to this effect if it cannot be frightened or can't see or hear Zax

Siege Monster. Zax deals double damage to objects and structures.

Powerful Build. Zax counts as one size larger in regards to what he can lift/carry.

Legendary Resistance (3/day). When Zax fails a saving throw, he can choose to succeed instead.

Multiattack. Zax makes three giant hammer attacks.

Giant Hammer. Melee Weapon Attack: +17 to hit, reach 10 ft, one target. Hit: 12 (2d12 + 6) Bludgeoning damage.

Earth Slam (recharge 5-6). Zax slams his hammer into the ground, causing the earth to erupt upward in 50-foot line that is 5 feet wide. Each creature in that area must succeed on a DC 21 Dexterity saving throw, taking 60 (10d12) bludgeoning damage on a failed save, or half as much on a successful one.

Bloody Rampage. When Zax takes damage, he makes one attack against a random creature within his reach.

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

Attack. Zax makes a weapon attack.

Bellow (Costs 2 Actions). Zax yells menacingly at one creature he can see within 60 feet of him. That creature must succeed on a DC 17 Wisdom saving throw or become frightened of him for 1 minute. If the creature is already frightened, it becomes stunned instead. 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 Zax's Bellow for the next 24 hours.

Reaping Hammer (costs 3 actions). Zax makes one hammer attack against each creature within reach. If the attacks hit, the targets must succeed on a DC 21 Strength saving throw or be pushed 10 feet away and knocked prone.