Celestian, The Far Wanderer

Divine Being. Celestian can't be surprised and can't be changed into another form against his will.

Divine Discorporation. When Celestian drops to 0 hit points his body is destroyed but his essence travels back to his domain in the Astral Plane, and he is unable to take physical form for a time.

Limited Magic Immunity. Unless he wishes to be affected, Celestian is immune to spells of 6th level or lower. He has advantage on saving throws against all other spells and magical effects.

Legendary Resistance (5/day). If Celestian fails a saving throw, he can choose to succed instead.

Astral Weapons. Celestian's weapon attacks are magical. When Celestian hits with any weapon, the weapon deals an extra 4d8 force damage (included in the attack)

Innate Spellcasting (Lesser Deity). Celestian can innately cast most spells that involve movement or travel aswell as several spells common to divine beings, his spellcasting ability is Charisma (spell save DC 26, +18 to hit with spell attacks). He can innately cast the following spells, requiring no components:
At-Will(Portifolio): dimension door, far step, feather fall, find the path, fly, jump, levitate, longstrider, misty step, plane shift, scatter, steel wind strike, teleport, thunder step, word of recall.
At-Will(Standard Divine Spells):  alter self, continual flame, darkvision, detect evil and good, detect magic, detect poison and disease, dispel magic, find traps, geas, greater invisibility, lesser restoration, mirror image, remove curse, tongues, zone of truth.
3/day: command(as a 6th-level spell), greater restoration, heal, resurrection, etherealness.
2/day:  antimagic field, divine word, gate, holy aura, power word heal, symbol.
1/day: globe of invulnerability(as an 8th-level spell), power word kill, regenerate, wish

Spellcasting. Celestian is a 20th level spellcaster. His spellcasting ability is intelligence (spell save DC 27, +19 to hit with spell attacks). Celestian has the following spells prepared:
Cantrips (at will): fire bolt, green-flame blade, light, minor illusion, sacred flame, thaumaturgy, word of radiance
1st level (4 slots): absorb elements, bless, magic missile, protection from evil and good, silent image, sanctuary, shield, shield of faith, zephyr strike.
2nd level (3 slots): blur, darkness, flaming sphere, invisibility, mirror image.
3rd level (3 slots): fireball, haste, hypnotic pattern, lightning bolt, major image, minute meteors.
4th level (3 slots): banishment, gravity sinkhole, greater invisibility, sickening radiance.
5th level (2 slots): dawn, swift quiver, teleportation circle, wall of light.
6th level (1 slot): gravity fissure, sun beam.
7th level (1 slot): crown of stars, reverse gravity.
8th level (1 slot): dark star, sunburst.
9th level (1 slot): ravenous void.

Aurora Borealis (Recharge 5-6). As a bonus action, Celestian creates a sheet of dancing, shifting light, as a 10-foot-radius, 30-foot-high cylinder in a point within 60 feet of him. It lasts for 1 minute (or until Celestian chooses to dispel it). When a creature enters the Aurora Borealis for the first time on a turn or starts its turn there, it is assaulted by the fiery radiance of the lights and must make a DC 27 Constitution saving throw. It takes 39 (6d12) radiant damage on a failed save, or half as much on a successful one.

Comet (Recharge 5-6). As an action, Celestian calls forth a flaming missile which strikes one target within 120 feet of him. The target must make a DC 27 Dexterity saving throw taking 54 (12d8) fire damage or half as much on a successful one. Also, on a failed save, the target aswell as all objects it is wearing or carrying start to burn, at the end of each of its turns the target repeats the saving throw, it takes 2d8 fire damage on a failed save and the flames cease on a successful one. These magical flames can't be extinguished by nonmagical means, but they are automatically quenched after one minute.
If damage from the comet kills its target, it is turned to ash.

Space Chill (Recharge 5-6). As an action, Celestian brings a wave of cold that manifests as a 20-foot-wide 100-foot-long line of cold vacuum. Each creature within the area must make a DC 27 Constitution saving throw taking 27 (6d8) cold damage plus 36 (8d8) force damage on a failed save, or half as much damage on a successful one.
A plant creature or a magical plant inside the area makes the saving throw with disadvantage, and the vacuum deals maximum damage to it.
A nonmagical plant that isn't a creature, such as a tree or shrub, inside the area doesn't make a saving throw, it simply withers and dies.

Star Calling (1/Dawn). As an action, Celestian can summon through a portal 1d4 Devas to aid him, if he is under the starry sky he can summon 3 more Devas through the same portal

Multiattack. Celestian makes three weapon attacks.

Spear of Collapsing. Melee Weapon Attack: +20 to hit, reach 5 ft. or 10 ft (when enlongated) or range 20/60 ft., one target. Hit: 18 (2d6 + 11) piercing damage plus 18 (4d8) force damage or 20 (2d8 + 11) piercing damage plus 18 (4d8) if used with two hands to make a melee attack.
While holding this 5-foot magical spear, Celestian can speak a command word to turn it into a 10-foot long magical spear and vice versa.

Battleaxe of Returning. Melee Weapon Attack: +19 to hit, reach 5 ft. or range 40/80 ft., one target. Hit: 19 (2d8 + 10) slashing damage plus 18 (4d8) force damage, or 21 (2d10 + 10) slashing damage plus 18 (4d8) force damage, if used with two hands. When thrown, the battleaxe returns to Celestian's hand

Magical Shortsword. Melee Weapon Attack: +22 to hit, reach 5 ft., one target. Hit: 20 (2d6 + 13) piercing damage plus 18 (4d8) force damage.

Unbreakable Dagger. Melee Weapon Attack: +23 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 19 (2d4 + 14) piercing damage plus 18 (4d8) force damage.

Magical Longbow. Ranged Weapon Attack: +23 to hit, range 150/600 ft., one target. Hit:  23 (2d8 + 14) piercing damage plus 18 (4d8) force damage.

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

At-Will Spell. Celestian casts one of his at-will spells.

Attack. Celestian makes one weapon attack

Star Shine (Costs 2 actions). Celestian targets up to four creatures within a 60-foot cone of him. A blazing white sheet of light issues from his eyes, all four targets must succed on a DC 26 Constitution Saving Throw or be blinded until the end of Celestian's next turn.