Magic Resistance. Yaggdytha, The Star Seed has advantage on saving throws against spells and other magical effects.

Legendary Resistance. (6/day). If Yaggdytha, The Star Seed fails a saving throw, it can choose to succeed instead. 

Higher-Dimensional Perspective. As a being of a higher dimension, Yaggdytha, The Star Seed can extend his turn to three actions. 

Higher-Dimensional Body. Has advantage against all saving throws and damage rolls.

Beyond Comprehension. If a target misses an attack on Yaggdytha, The Star Seed, they must roll a DC 18 CON Saving Throw or be frightened for the next three turns.

Ascended Immutable Form. The dragon is immune to any spell or effect that would alter its form. Additionally, any spell of 6th Level or Lower that attempts to lower its stats or negatively effect it are nullified.

Wails of the Unborn. Humanoids within 60 feet of Yaggdytha, The Star Seed that can hear it have disadvantage on Constitution saving throws to maintain concentration.

Siege Monster. Yaggdytha, The Star Seed deals double damage to objects and structures.

Aura of Decay. Yaggdytha, The Star Seed passively decays its surroundings dealing 2d6 necrotic damage to everything within 100ft of it.

Erased from Existence. If Yaggdytha, The Star Seed brings an enemy to 0 hp, they must roll a DEX 18 Saving Throw or they get erased from existence. 

Magic Weapons. Yaggdytha, The Star Seed's weapons attacks are magical.

Multiattack. Yaggdytha, The Star Seed attacks five times with its shadow strike.

Shadow Strike. Yaggdytha, The Star Seed attacks with a shadow tendril. +10 to hit, deals (4d10+5) damage, 30ft of range.

Shadow Flames. Yaggdytha, The Star Seed breathes pure, pitch-black flames in a 100ft cone. All opponents in that radius must roll a DC DEX 22 saving throw or take (10d8+10) fire damage and (2d10+10) necrotic damage.

Ultimate Void. (1/day). Yaggdytha, The Star Seed channels an infinitesimal fraction of the power of its true form, create a super-massive blackhole that crushes all that enter it with infinite force. All opponents within a 1000ft radius must roll a DC DEX saving throw of 25 or better or get sucked into the black hole, taking (20d20+50) force damage. On success, they still get pulled in, but take no damage as the black hole acts as a wormhole and transports them to an alternate dimension.

Scream. On an attack roll that would hit Yaggdytha, The Star Seed, it can choose to only receive half damage and scream, forcing all entities within a 30ft circle to roll a DEX 30 Saving Throw or be knocked prone and take 1d10 force damage.