The Seven Gates of the Underworld is the last puzzle of Eternal Prison, which leads straight to Hel, the Guardian of the area. For each door you go through, you will temporarily lose one of your treasures, and be unable to use them.

The order is:

  • Icefire Treetop (D-6); Defeat Vidofnir with the Flame Torc.
  • Eternal Prison - Gloom (E-1); Upon arrival at D-6, crawl through the wall to the left, just above the death trap.
    • You will lose the Grapple Claw. (Gold-Gleaming Wrist Guard)
  • Eternal Prison - Doom (C-7)
  • Eternal Prison - Gloom - (D-5); pass through the lasers using the Clay Doll Outfit.
  • Eternal Prison - Gloom (C-6)
    • You will lose the Feather. (Golden Wings)
  • Eternal Prison - Doom (E-4); Hraesvelgr must be defeated.
    • You will lose the Anchor. (Something Repurposed)
    • Take great care not to fall down into the pit at D-6 and be particularly wary of the frost covered trap door here (otherwise you will have to restart the puzzle as you can't double jump).
    • You will notice that you can't get up to the top right anymore without the feather :(. Don't panic though; break the small boulder with bombs at (D-5) above the wheel of ages and push the column from left to right (about half way).
  • Eternal Prison - Gloom (B-2); the door should reveal itself automatically.
    • You will lose the Glove. (Glove of Power)

After finishing the sequence, a ladder appears at Eternal Prison - Doom (B-3), allowing you to go down the ladder to reach the Doom Grail Tablet, as well as Hel.