Charge. If the minotaur moves at least 10 feet straight toward a target and then hits it with a gore attack on the same turn, the target takes an extra 9 (2d8) piercing damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be pushed up to 10 feet away and knocked prone. If the creature fails the saving throw, Graxis can immediately make two attacks with its greataxe.

Labyrinthine Recall. The minotaur can perfectly recall any path it has traveled.

Reckless. At the start of its turn, the minotaur can gain advantage on all melee weapon attack rolls it makes during that turn, but attack rolls against it have advantage until the start of its next turn.

Undying Curse (Mythic Trait, Recharges each night at dusk). If Graxis is reduced to 0 hit points, he doesn't die or fall unconscious. Instead, he regains 60 hit points. His cursed blood oozes from the cuts in his body and his eyes glow red with blind rage. His Legendary Actions are replaced by his Mythic Actions

Multiattack. The minotaur makes two melee attacks with its greataxe.

Greataxe. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 17 (2d12 + 5) slashing damage.

Gore. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 5) piercing damage.

Cursed Transformation (Mythic Only). If Graxis is hit with a melee attack, his cursed blood splatters against the attacker. Graxis can use his reaction to force this creature to make a DC 14 Wisdom saving throw or be magically transformed into a bull as if though affected by the Polymorph spell.

Move. Graxis can move up to his speed without provoking attacks of opportunity. If he moves 10 or more feet straight at a creature and then stops adjacent to them, the creature must make a DC 14 Strength saving throw or fall prone.

Gore. Graxis lashes out, making one Gore attack.

Keen Senses. Graxis makes a perception check, at advantage if scent is involved.

Enter the description for how mythic actions work for your monster here.

Spew Blood (Costs 1 Action). Graxis spits cursed blood in a 15-foot cone. Each creature in the cone must make a DC 14 Constitution saving throw, taking 14 (4d6) necrotic damage on a failed save, or half as much damage on a successful one.

Windmill of Bones (Costs 1 Action). Graxis flails out at all creatures in reach. Each creature within 5 feet of Graxis must make a DC 16 Dexterity saving throw. On a failed saved, a creature takes 10 (3d6) bludgeoning damage and is knocked prone. On a successful save, the creature takes half damage and is not knocked prone.

Furious Gaze (Costs 2 Actions). Graxis focuses his gaze on one creature within range. That creature must make a DC 14 Wisdom Saving throw or be overcome with the same bloodlust felt by Graxis. On a failed save, the target loses the ability to distinguish friend from foe, regarding all creatures it can see as enemies until the effect ends. Whenever the affected creature chooses another creature as a target, it must choose the target at random from among the creatures it can see within range of the attack, spell, or other ability it’s using. If an enemy provokes an opportunity attack from the affected creature, the creature must make that attack if it is able to. The affected creature can make an additional saving throw at the end of each of their turns.