Upsala, The Dragon of time

Draconic Awakening (Recharges after a Short or Long Rest). If Asla would be reduced to 0 hit points, her current hit point total instead resets to 750 hit points, she recharges her Breath Weapon, and it regains any expended uses of Legendary Resistance. and gains access to its mythic abilities 

Final recall (Mythic only) when Absla is reduced to 0 hit points she reverts time by 24 hours, any events that took place are undone and she loses 1 sanity, this trait does not function if she is killed outright, such as from the effects of the power word kill spell or another spell that causes instant death 

Aura of slowed time, when Absla is forced to make a Dex saving throw from an effect she can see, she takes no damage on a success and half as much damage on a failure, this trait does not function if the triggering effect takes place within 10 feet of her

Legendary Resistance (5/Day). If the Absla fails a saving throw, she can choose to succeed instead.

time on my side Absla's allies gain a plus 10 to their initiative rolls and her enemies have a minus 10 to their initiative rolls

Time altered recovery, (Mythic only) Absla regains 20 hit points at the start of her turn 

 3/day each: Haste, Slow, steal wind strike 

2/day each: Time stop, Forsight, Time ravage, 

 Multiattack. The aspect makes one Bite attack, one Claw attack, and one Tail attack.

Bite. Melee Weapon Attack: +19 to hit, reach 20 ft., one target. Hit: 23 (2d12 + 10) piercing damage plus 19 (3d12) necrotic damage.

Claw. Melee Weapon Attack: +19 to hit, reach 15 ft., one target. Hit: 21 (2d10 + 10) slashing damage. If the target is a Huge or smaller creature, it is grappled (escape DC 20) and is restrained until this grapple ends. The aspect can have only one creature grappled this way at a time.

Tail. Melee Weapon Attack: +19 to hit, reach 15 ft., one target. Hit: 23 (2d12 + 10) bludgeoning damage. If the target is a creature, it must succeed on a DC 24 Strength saving throw or be knocked prone.

Breath Weapon (Recharge 5–6). The greatwyrm exhales tempral force in a 300-foot cone. Each creature in that area must make a DC Chrisma saving throw. On a failed save, the creature takes 76 (12d12) necrotic damage and is aged 4d20 + 10 years. On a successful save, it takes half as much damage and is not aged, if this effect would age a target beyond its normal life span the target dies

Mass statis:  Absla targets any number of creatures and objects she can see within 120 feet of her. Each targeted creature must succeed on a DC 26 Chrisma saving throw or be paralyzed in the Abslas Aura of time. At the end of a creature’s turn, it can repeat the saving throw, ending the effect on itself on a success.

Regression: one creature within 5 feet of Absla must make a DC 26 Chrisma saving throw. on a failure it is transformed into a child, its stats are replaced by this new form and at the start of its turn it must make a DC 20 intelligence saving throw, on a success it may act normally, on a failure its mind begins to regress to a childlike state, and it suffers the effects of feeble mind, a greater restoration or wish spell reverts the target to its original age

Banish through time, Absla casts banishment, transporting her target to a different time rather than a harmless demi plane, the target must make a Chrisma save dc 26, on a failure target is cast into the future or past, (her choice,) if the target remains there for the duration they are stuck there permanently 

Entropic wave Absla casts disintegrate at 9th level, if the save fails, the target also ages 1d10 × 10 years,

Weight of Ages: Absla flares with chronomantic energy. Each creature of her choice in a 60-foot-radius sphere centered on her must make a DC 26 constitution saving throw. On a failed save, the creature takes 36 (6d12) necrotic damage, taking half as much on a successful save. regiuardless of wherater the save succeads or failed the target ages 1d4 x 10 years

Wither to Ash: absla makes a melee spell attack, on one target creature she can see within range, putting its physical form through the devastation of rapid aging. The target takes 10d12 necrotic damage, the target also ages to the point where it has only 30 days left before it dies of old age. In this aged state, the target has disadvantage on attack rolls, ability checks, and saving throws, and its walking speed is halved. Only the Wish spell or the Greater Restoration spell can end these effects and restore the target to its previous age.

darkest timeline Absla peers through multiple timelines and summons froth an echo of a creature from the darkest timeline (It appears to be the same as the original, but it has half the creature's hit point maximum and is formed without any Equipment. Otherwise, the Illusion uses all the Statistics of the creature it duplicates.)

World ending presence, each creature of the Absla's choice within 120 feet of her and aware of her must succeed on a DC 26 Wisdom saving throw or become frightened for 1 minute. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to this effect for the next 24 hours.  While frightened by this Spell, a creature must take the Dash action and move away from Her by the safest available route on each of its turns, unless there is nowhere to move. If the creature ends its turn in a location where it doesn’t have line of sight to her, the creature can make a Wisdom saving throw. On a successful save, the spell ends for that creature, if a creature fails this save by 5 or more it is both frightened and paralyze 

Change Shape. The greatwyrm magically transforms into any creature that is Medium or Small, while retaining its game statistics (other than its size). This transformation ends if Absla is reduced to 0 hit points or uses a bonus action to end it.

Final moments, when Absla reduces a creature to 0 hit points, she can use a bonus action to trap them in times, a creature trapped in this way does not make death saving throws, but is instead paralyzed, and to all immune damage and healing, a wish spell or dispel magic ends this effect, otherwise it lasts until the set condition for the spell to end early is met, The condition can be anything you choose, but it must occur or be visible within 1 mile of the target. Examples include after 1,000 years or when the Tarrasque awakes. 

Blast from the past, (mythic only) when a creature takes damage from an attack roll made by Absla she can use a bonus action to force the creature to make a con saving throw, on a failure the creatures body is racked with the pain from past injury's, if the target took damage within the last round it takes that damage again, and if the target tries to cast a spell, it must first succeed on a Constitution saving throw, or the casting fails and the spell is wasted. this effect lasts until the end of the targets next turn 

Temporal shunt, when a creature makes an attack roll or starts a spell cast the target must make a DC 24 intelligence save or become trapped in time for 1 round. Their attack or spell is wasted, and they don’t know you cast the spell on them. The banishment lasts until the start of their next turn

Follow through, as a reaction when a target misses a melee attack against Absla she can force them to make a strength throw or become restrained

Chronal Shift you can magically exert control over the flow of time around a creature. As a reaction, after you or a creature you can see within 30 feet of you makes an attack roll, an ability check, or a saving throw, you can force the creature to reroll. The target must use the result of the second roll.

all the time in the world (mythic only) Absla gains a second reaction 

Convergent Future (Mythic only) you can peer through possible futures and magically pull one of them into events around you, ensuring a particular outcome. When you or a creature you can see within 60 feet of you makes an attack roll, an ability check, or a saving throw, you can use your reaction to ignore the die roll and decide whether the number rolled is the minimum needed to succeed or one less than that number (your choice).

The Absla can take 5 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. She regains spent legendary actions at the start of its turn.

Claw. (Cost 1) The Absla makes one Claw attack.

Time pass (Cost 1) ten rounds of combat pass instantly, spell effects are resolved as if that amount of time had elapsed 

Temporal teleport (costs 1) Absla teleports up to 120 feet in any direction 

Epoch anchor (Cost 2)  Absla Warps time in a 40-foot area, targets that start their turn in range must make a DC 26 Chrisma saving throw or be affected by the slow spell 

Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 30 feet of the dragon must succeed on a DC 26 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

pull through time (Costs 3) uses her darkest timeline ability

Rewind (Costs 4), one target with 60 feet must make a DC 26 Chrisma saving throw or have the effects of their last turn undone as time is rewritten

(Costs 5) Weight of Eons. The Absla flares with chronomantic energy. Each creature of her choice in a 60-foot-radius sphere centered on her must make a DC 26 charisma saving throw. On a failed save, the creature takes 36 (6d12) necrotic damage successful save, the creature takes half as much damage, a mortal target effected by this ability dies of old age, an immortal target becomes mortal with a life span of 2000 years, but is afterwards immune to this ability 

No time like the present (costs 5) Absla immediately takes a turn in combat