Ancient Time Greatwrym

Spellcasting. The greatwyrm is a 20th level wizard. It knows all spells (2014 core and expanded spells, homebrew spells are up to DM), see common prepared spells below, the prepared spells can be interchanged at the DM’s discretion. The greatwyrm does not require material components. See spell description for casting time. -/ Spell save DC 30; Spell attack mod +20 \-Cantrips (at will). Mage hand, control flames, message, mending, Prestidigitation
1st Level (8 spell slots). Alarm, identity, shield, detect magic
2nd Level (4 spell slots). Enlarge/reduce, arcane lock, skywrite 
3rd Level (4 spell slots). Counterspell, remove curse, dispel magic 
4th Level (4 spell slots). Banishment, greater invisibility, Hallucinatory Terrain
5th Level (4 spell slots). Mislead, legend lore, planar binding
6th Level (3 spell slots). Guards and wards, mass suggestion
7th Level (3spell slots). Plane shift, teleport, symbol
8th Level (2 spell slots). Reality break, demiplane (new demiplanes are doubled in size when created by the greatwyrm) 
9th Level (2 spell slots). Time stop, time ravage

Timeless Nature. The greatwyrm doesn't require food or drink and does not need to breathe. It is also immune to any spell or magical effects that alters or stops time. It can also survive outside of time.

Temporal form. The greatwyrm magically transforms into any creature that is Large or Smaller, while retaining its game statistics and traits (other than its size.) It keeps its legendary resistances, but it cannot gain any uses of legendary resistance from the new form. It also keeps its, reactions, bonus actions, its temporal isolation action and its legendary actions if the new form is capable of using them(Ex. Has wings for Wing attack). The Greatwyrm gains temporary hit points equal to the average hit points of the new form, these hit points are added to any temporary hit points gained by any other effect. This transformation ends if the dragon is reduced to 0 temporary hit points or uses a bonus action to end it, if it dose so it loses the temporary hit points. 

Time Step. The greatwyrm magically teleports to an unoccupied space it can see within 240 feet of it.

Temporal Echo. The greatwyrm creates 1d8+1 copies of itself. These copies appear instantly anywhere in a 90 ft. Radius around the greatwyrm. The copies have the same statistics as the greatwyrm but have 1 health, they are exact copies and act freely as the greatwyrm would, they prioritize the life and orders of the original over everything else, including their existence. The copies appear in the form the greatwyrm was in at the time of this action being taken. they do not gain any conditions that the greatwyrm has, they also cannot gain any hit points or temporary hit points. The copies are indistinguishable from the greatwyrm and can take any action that the greatwyrm can, including attacks and temporal form. As a free action the greatwyrm can trade places with any of the copies instantly at any distance across time and planes. The copies dissipate when the greatwyrm dismisses them, they chose to or they reach 0 hit points. The copies memories go to the greatwyrm when they dissipate regardless of the method of death. Only one set of copies can exist at once, more cannot be created unless all previous copies are dead. 

The greatwyrm can use each reaction once per round, but only one per turn. 

Reactive Rend. After using Legendary Resistance or in response to being hit by an attack roll, the greatwyrm makes one Rend attack.

Slow Time. Immediately after a creature the greatwyrm can see ends its turn, the greatwyrm targets a creature it can see within 90 feet of itself that is weakened by its Time Breath. Until the weakened effect ends on the target, its speed becomes 0, and its speed can't increase.

Time Slip. The greatwyrm takes no damage from an attack made against it, provided it can see the attacker. The greatwyrm can then immediately teleport, along with any equipment it is wearing or carrying, up to 60 feet to an unoccupied space it can see.

Legendary Action Uses: 5. Immediately after another creature's turn, The greatwyrm can expend a use to take one of the following actions. The greatwyrm regains all expended uses at the start of each of its turns.

Tail (Cost 1 Action). Melee Weapon Attack: +18 to hit, reach 30 ft., one target. Hit: 19 (2d8 + 10) bludgeoning damage. If the target is a creature, it must succeed on a DC 26 Strength saving throw or be knocked prone.

Wing Attack (Costs 2 Actions). The greatwyrm beats its wings. Each creature within 30 feet of it must succeed on a DC 26 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The greatwyrm can then fly up to 30 ft. Without evoking opportunity attacks. 

Temporal Fling (Cost 3 Actions). The greatwyrm attempts to fling a creature it can see within 60 feet of itself forward through time. The target must succeed on a DC 18 Wisdom saving throw or take 26 (4d12) psychic damage and move 1 round forward in time. A target moved forward in time vanishes for the duration. When the effect ends, the target reappears in the space it left or in an unoccupied space nearest to that space if it's occupied.

If the greatwyrm's Temporal Rewind trait has activated in the last 2 hour, it can use the options below as legendary actions. It also gains the following traits for the duration.

Mythic Feats.
- Temporal forms. if the greatwyrm alters its form by using temmporal form it keeps all mythical traits and actions for the duration as long as the new form is capable of using them. 

-  Multiattack. The greatwrym makes 1 additional rend attack when taking the attack action, for a total of 6.

- Legendary actions. The greatwym gains 3 additional legendary actions, for a total of 8.

- Temporal enhancement. The greatwyrm is now empowered by time flowing through it. The temporal isolation effect range is doubled (240 ft. Radius) its cooldown is halved (4-5 turns) and the greatwyrm can isolate any creatures of it choice within the range from its effects(free action), causing those creatures to stop in time, these creatures are stopped in time and cannot be harmed, moved or targeted by a spell or magical effect in any way while the effect is active. If temporal isolation is active when Temporal rewind is activated it immediately gains these traits and its duration is reset. 

Bite (Cost 1 Action). Melee Weapon Attack: +20 to hit, reach 10 ft., one target. Hit: 36 (4d12 +12) piercing damage. On a successful hit if the target creature is Large or smaller, make a DC 26 Dexterity saving throw on a fail the creature is grappled inside the greatwyrms mouth. As long as the creature is grappled it has disadvantage on all saving throws and immediately fails to resist the greatwyrms time breath. The creature can either be magically teleported away from the greatwyrm or it can take an action to make a DC 26 Dexterity or Strength saving throw to escape the grapple. On a failed attempt to escape the grapple the creature takes 1d12 piercing damage. Up to one large creature or  2 medium or smaller creatures can be grappled by the greatwyrm at once. 

Temporal Flare (Costs 2 Actions). The greatwyrm flares with elemental energy. Each creature in a 60-foot-radius sphere centered on the greatwyrm must succeed on a DC 26 Dexterity saving throw or take 25 (6d8) Force damage.

 Temporal Lag (Cost 2 Actions). The greatwyrm slows time for each creature within 60 feet of itself. Until initiative count 20 of the next round, the affected creature can move or take an action on its turn, not both. The creature also can't take a reaction or a bonus action.