Legendary Resistance [3/Day]. If Auppenser fails a saving throw, he can choose to succeed instead.

Magic Resistance. Auppenser has advantage on saving throws against spells and other magical effects.

Arcane Pantomath. Auppener can identify a spell without using an action if he can see or hear it being cast, or if he can see or hear its ongoing magical effects at any point during its duration. In addition, Auppener instantly learns the properties of a magic item if he can see the item.

Divine Awareness. Auppener knows if he hears a lie.

Spellcasting. The Auppener is a 20th-level spellcaster. His spellcasting ability is [Intelligence] (spell save DC 21, +7 to hit with spell attacks).

Cantrips (at will): Mage hand, Minor Illusion, Prestidigitation, Thunderclap  

1st level (4 slots): Absorb Elements, Magic Missile, Witch Bolt, Feather Fall

2st level (3 slots): Blindness/deafness, Enlarge/Reduce, Borrowed Knowledge

3rd level (3 slots): Counterspell, dispel magic, enemies abound

4th level (3 slots): Phantasmal Killer, Polymorph, Sickening Radiance

5th level (2 slots): Enervation, Telekinesis

6th level (2 slots): Chain Lighting, Disintegrate

7th level (2 slot): Crown of Stars, Reverse Gravity

8th level (1 slot): Mind Blank

9th level (1 slot): Meteor Swarm

Multiattack. The solar makes two greatsword attack.

Greatsword. Melee Weapon Attack : +9 to hit, reach 5 ft., one target. Hit: (4d6 + 8) slashing damage plus (4d8) radiant damage

Absorb Elements. 

1st-level abjuration

Casting Time: 1 reaction, which you take when you take acid, cold, fire, lightning, or thunder damage
Range: Self
Components: S
Duration: 1 round

The spell captures some of the incoming energy, lessening its effect on you and storing it for your next melee attack. You have resistance to the triggering damage type until the start of your next turn. Also, the first time you hit with a melee attack on your next turn, the target takes an extra 1d6 damage of the triggering type, and the spell ends.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the extra damage increases by 1d6 for each slot level above 1st.

Feather Fall. 

Auppener 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. Auppener regains spent legendary actions at the start of their turn.

Teleport (Costs 1 Actions).The solar magically teleports, along with any equipment it is wearing or carrying, up to 120 ft. to an unoccupied space it can see.

Wish (Cost 2 Actions). 

• Casting Time: 1 action
• Range: Self
• Target: Self
• Components: V
• Duration: Instantaneous
• Classes: Sorcerer, Wizard
• Wish is the mightiest spell a mortal creature can cast. By simply speaking aloud, you can alter the very foundations of reality in accord with your desires.
  The basic use of this spell is to duplicate any other spell of 8th level or lower. You don’t need to meet any requirements in that spell, including costly components. The spell simply takes effect.
  Alternatively, you can create one of the following effects of your choice:
  You create one object of up to 25,000 gp in value that isn’t a magic item. The object can be no more than 300 feet in any dimension, and it appears in an unoccupied space you can see on the ground.
  You allow up to twenty creatures that you can see to regain all hit points, and you end all effects on them described in the greater restoration spell.
  You grant up to ten creatures that you can see resistance to a damage type you choose.
  You grant up to ten creatures you can see immunity to a single spell or other magical effect for 8 hours. For instance, you could make yourself and all your companions immune to a lich’s life drain attack.
  You undo a single recent event by forcing a reroll of any roll made within the last round (including your last turn). Reality reshapes itself to accommodate the new result. For example, a wish spell could undo an opponent’s successful save, a foe’s critical hit, or a friend’s failed save. You can force the reroll to be made with advantage or disadvantage, and you can choose whether to use the reroll or the original roll.
  You might be able to achieve something beyond the scope of the above examples. State your wish to the GM as precisely as possible. The GM has great latitude in ruling what occurs in such an instance; the greater the wish, the greater the likelihood that something goes wrong. This spell might simply fail, the effect you desire might only be partly achieved, or you might suffer some unforeseen consequence as a result of how you worded the wish. For example, wishing that a villain were dead might propel you forward in time to a period when that villain is no longer alive, effectively removing you from the game. Similarly, wishing for a legendary magic item or artifact might instantly transport you to the presence of the item’s current owner.
  The stress of casting this spell to produce any effect other than duplicating another spell weakens you. After enduring that stress, each time you cast a spell until you finish a long rest, you take 1d10 necrotic damage per level of that spell. This damage can’t be reduced or prevented in any way. In addition, your Strength drops to 3, if it isn’t 3 or lower already, for 2d4 days. For each of those days that you spend resting and doing nothing more than light activity, your remaining recovery time decreases by 2 days. Finally, there is a 33 percent chance that you are unable to cast wish ever again if you suffer this stress.

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

Mythic Action Name (Costs # Actions). Enter the description for your mythic action.