Attack the Abyssal Totem at the end of the dungeon. If you die in the dungeon just use the totem gateway to be instantly portalled back into the temple.
This item requires you to complete a specific quest before you can pick it up!
Hoshar ibn Jalaq tells you, "You may be able to help me... I would ask you to seek out a powerful Mukkir known only as the Progenitor. Its ichor has some unique properties, and may be of great use to us in our efforts to combat the demon known as Grael. If you are strong enough to fight mighty Mukkir, venture to 86.4 N, 57.4 E on the Dark Isle, and bring me the ichor of the Progenitor."
You give Hoshar ibn Jalaq Progenitor's Ichor.
Hoshar ibn Jalaq tells you, "Well done. The Ichor of Hastar the Misbegotten is indeed helpful. It allows me to make this token, which will gain you entrance to the chambers of Grael's Abyssal Totem. Simply give this Gateway Token to the Abyssal Totem Gateway on the Dark Isle, and a portal should open up for you. Once you have gained access to the Abyssal Totem Temple, destroy the Abyssal Totem, and that will help split Grael's power..."
Hoshar ibn Jalaq gives you Abyssal Gateway Token.
The Gateway of the Abyssal Totem seems to sense your presence and recognizes you. It teleports you into the Temple of the Abyssal Totem...