Alone in the Dark: Iðunn the Lost Oracle

Blessing of Bahamut. While Iðunn is wearing no armor and wielding no shield, her AC includes her Wisdom modifier. In addition, a creature that hits Iðunn with a melee attack while within 5 feet of her takes 9 (2d8) force damage.

Innate Spellcasting. Iðunn's spellcasting ability is Wisdom (spell save DC 13, +5 to hit with spell attacks). She can innately cast the following spells, requiring no material components:

At will: guidance, light, thaumaturgy

3/day each: bless, guiding bolt, healing word, hold person

1/day each: augury, scrying

Multiattack. Iðunn can use her Mournful Presence. She then makes three attacks: one with her rending claws and two with dragonstone blast.

Rending Claws. Melee Spell Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) force damage.

Dragonstone Blast. Ranged Spell Attack: +5 to hit, range 120 ft., one target. Hit: 5 (1d10) force damage.

Mournful Presence. Each creature of Iðunn's choice that is within 120 feet of her and aware of her must succeed on a DC 24 Wisdom saving throw or become overwhelmed by feelings of despair. The creature becomes frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to Iðunn's Mournful Presence for the next 24 hours.

Dragon God's Insight (3/Day). When Iðunn or a creature she can see makes an attack roll, a saving throw, or an ability check, Iðunn can cause the roll to be made with advantage or disadvantage.

Once per day, when Iðunn's hit points have been reduced to less than half, she may use the following mythic action:

Change Shape. Iðunn magically polymorphs into her draconic form. She reverts to her true form if she dies. Any equipment she is wearing or carrying is absorbed by the new form.