Apocrypha

Hermaeus Mora's realm, entered by reading the Black Books.

Quests here

At the Summit of Apocrypha (Dragonborn): After The Gardener of Men, Frea asks you to end it. Read Waking Dreams, the Black Book from Miraak's temple. Reward: Miraak's mask, robes, sword and staff, and a word of Dragon Aspect.

Hah (Mind) of Bend Will: Taught by Hermaeus Mora in Apocrypha during The Gardener of Men.
Diiv (Wyrm) of Dragon Aspect: Word wall in Apocrypha, on the climb to the summit during At the Summit of Apocrypha.

Miraak's Robes (Dragonborn) – Clothing: Taken from Miraak's remains at the end of At the Summit of Apocrypha.
Miraak's Gloves (Dragonborn) – Clothing: Taken from Miraak's remains at the end of At the Summit of Apocrypha.
Miraak's Boots (Dragonborn) – Clothing: Taken from Miraak's remains at the end of At the Summit of Apocrypha.
Miraak (Dragonborn): Taken from Miraak's remains at the end of At the Summit of Apocrypha.
Conjure Seeker (Dragonborn) – Conjuration: Not sold anywhere. Once your Conjuration reaches 40 it can turn up inside the Black Books, The Sallow Regent and The Winds of Change among them.
Miraak's Sword (Dragonborn) – Sword: Taken from Miraak's remains at the end of At the Summit of Apocrypha.
Miraak's Staff (Dragonborn) – Staff: Taken from Miraak's remains at the end of At the Summit of Apocrypha.