Possessed by a Goddess. Alton is immune to any form of mind control
Spell Resistance. Alton has advantage on saves against spells and magical effects.
Frightful Presence. At the start of combat, each creature of Alton's choice within 120 ft must make a DC 17 Wisdom saving throw or become frightened of him for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on a success. On a success, a creature becomes immune to this effect for 24 hours.
Multiattack. Alton makes two Longsword attacks, and one Doom attack
Longsword: +8 to hit, reach 5 ft., Hit: (1d8 + 5) slashing damage.
Doom: +8 to hit, reach 5 ft, Hit: (1d8 + 8) psychic damage. Additionally, if the target was hit by one or more Longsword attacks this turn, they must make a Wis saving throw DC 17 for each time they were hit. On a failure, they take 1d8 additional psychic damage, and are unable to take reactions until the end of Alton's next turn. If they fail twice, they are incapacitated until the end of Alton's next turn, or until they receive at least 10 points of magical healing, or an ally spends an action to make a DC 15 Medicine check.
Deific Decay (Costs 2 Actions). All enemies within 60' must make a constitution save (DC 17) or take 2d6 poison damage and be poisoned for 1 round as a dark gas explodes outward, filling the air. Success means half damage and not poisoned.
Farian's Mercy (Costs 1 Actions). Alton teleports behind the last target hit by one of his single target attacks, and deals a powerful, spinning strike. The target must make a DC 17 Strength save or take 2d10+5 slashing damage, be knocked prone, and have its movement speed reduced to 5 feet until the end of its next turn. Success reduces the damage by half, and removes the negative effects.
Demonic Spiral (Costs 3 Actions). Alton's sword extends, growing into a blade of pure necrotic energy. He launches into a spin attack, slicing at all nearby enemies. +10 reach 15ft all targets in range hit: 1d8+5 slashing + 2d10 necrotic damage