Atrenu Zehlein, Psychic Grandmaster

Boiling Blood. Atrenu carries a deep seated rage against those who wronged him. When initiative is rolled, he gains a rampage die. This die is a d6, and increases by one step each turn he deals damage, up to a d12. Once per turn, when he rolls damage, he may roll this die and add it to his damage dealt. If he deals no damage during one of his turns, or becomes incapacitated, it reverts to a d6. Also, when he is reduced to zero hit points, he rolls his rampage die and adds his Constitution modifier to the result. If the result is higher than the excess damage of the attack, he is instead reduced to one hit point. He can expend 2 psi points to roll another rampage die and add it to this result.

Spellcasting (Psionics). Atrenu is a 20th-level spellcaster. His spellcasting ability is Intelligence (spell save DC 26, +18 to hit with spell attacks).

As opposed to other spellcasters, Atrenu is a Psion. He does not have spell slots; rather, he has Psi points that he can expend to cast various spells and amplify his powers. Atrenu has 30 Psi points, which he may use on the following abilities (following normal spellcasting rules):

Cantrips (at will, following rules for Psionic Mastery (3 points)): astral construct, denial, enhancing surge, lightning blast, phase rift, seeing, telekinetic force, thaumaturgy, telekinetic weapons, telepathic intrusion 

1st level (1 Psi point): arc flash, fission, thunderwave, jump, catapult, compelled query, command, cause fear , heroism, longstrider, unlocked potential, expeditious retreat, flicker, zephyr strike, detect good and evil, identify, future insight, protection from good and evil.

2nd level (2 Psi points): ball lightning, bolting, dust devil, levitate, shatter, psychic drain, detect thoughts, mind spike, suggestion, alter self, enlarge/reduce, lesser restoration, misty step, blur, pass without trace, augury, glimpse the future, locate object, nullify effect,

3rd level (3 Psi points): fly, erupting earth, fireball, lightning bolt, delve mind, fear, enemies abound, catnap, haste, fear, clairvoyance, dispel magic, counterspell, remove curse, blink, nondetection, thunderstep.

4th level (4 Psi points): otiluke's resilient sphere, tempest, wall of lightning, dominate beast, compulsion, confusion , freedom of movement, stoneskin, death ward, divination, banishment, dimension door.

5th level (5 Psi points): animate objects, wall of force, telekinesis, nova burst, thoron, dominate person, modify memory, telepathic bond, synaptic static, psionic storm, greater restoration, skill empowerment, legend lore, scrying, dispel evil and good, far step, steel wind strike.

1/day each: disintegrate, Zehlein's Investiture of the Archon, crown of stars, teleport, dominate monster, feeblemind, foresight, Zehlein's genetic unraveling

Legendary Resistance (3/day).: If Atrenu would fail a saving throw, he can choose to succeed instead.

Limited Magic Resistance. Unless he chooses to be affected, Atrenu is immune to spell effects of 5th level or lower. If the caster also has the Psionics feature or is also a Psion, this trait is nullified.

Psychic Power. Atrenu uses one of his Psychic powers, detailed below.

Kinetic Slam. Ranged Spell Attack: +18 to hit, reach 60 ft., 1 target. Hit: 34 (4d10 + 10) bludgeoning damage, and the target must make a DC 26 Strength saving throw or be knocked prone or thrown 25 feet in a direction of Atrenu's choice. 

Lightning Blast. Ranged Spell Attack: +18 to hit, range 30 ft., 1 target. Hit: 34 (4d10 + 10) lightning damage. A bolt of lightning then arcs to another creature within 20 feet of the original target, requiring another attack roll. Hit: 24 (4d6 + 10) lightning damage.

Mind Thrust. Ranged Spell Attack: +18 to hit, reach 60 ft., 1 target. Hit: 30 (4d8 + 10) psychic damage, and the target has disadvantage on attacks made against Atrenu until the start of his next turn. He can choose to deal no damage with this attack. 

Telekinetic Weapons. Atrenu mentally hurls up to four weapons within 15 feet of him that aren't being worn or carried, or are otherwise under his control. Ranged Spell Attack: +18 to hit, reach 15/30/60 ft. (depending on if the weapon has the heavy/special property, no properties, or the light property, respectively), 1 target per weapon. Hit: The weapon's normal damage dice plus 10 (Atrenu's Intelligence modifier).

Mindcleaver, the Blackened Blade. Atrenu hurls his personal sword towards a target within 30 feet. Ranged Spell Attack: +18 to hit, reach 30 ft., 1 target. Hit: 17 (1d8 + 1d4 + 10) slashing damage, and the target must make a DC 18 Intelligence saving throw. On a failure, the target's Intelligence score is reduced by one and Atrenu's Intelligence score is increased by one.

Precise Power. As a reaction to a ranged attack made against him or a target within 60 feet of him, Atrenu can add or subtract 2d4 from the attack roll.

Absorb Elements. Atrenu can channel his psychic abilities to replicate elemental effects. When Atrenu takes acid, cold, fire, lightning or thunder damage, he can use his reaction to gain resistance to the triggering damage type until the end of his next turn. Additionally, the next time he makes a melee attack on his next turn, his attack deals an additional 1d6 damage of the absorbed damage type.

Shield. When Atrenu would be hit with an attack, he can use his reaction to raise a psychic shield. When he does this, his AC increases by 5 until the start of his next turn.

Atrenu can take up to 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. Atrenu regains spent legendary actions at the start of his turn.

Move. Atrenu moves up to his speed without provoking opportunity attacks.

Psychic Power. Atrenu uses one of his Psychic Powers.

Shockwave (Costs 2 Actions). Atrenu unleashes a burst of telekinetic force in all directions. Each creature within 30 feet of him is pushed 5 feet back and must succeed on a Strength saving throw or take 8d6 bludgeoning damage and be knocked prone. A creature that succeeds takes half damage and is not prone.