It is in KingsIsle, about 58 steps north-east of the spot the map marks with that name.

And 8 down from the surface once you are there.

• 1 — KingsIsle, as the map itself names it
• 2 — the ground above the treasure

• A rope. You drop in through a hole, and a rope is how you climb back out.
• Something for demon, dragon lord and banshee — they live down there.

The chest is 8 floors under the surface. Going down over it, this is what each floor uses:

1. Ground: down through stairs.
2. 1 down: down through a hole.
3. 2 down: down through a hole.
4. 3 down: down through stairs.
5. 4 down: down through stairs.
6. 5 down: down through stairs.
7. 6 down: down through stairs.
8. 7 down: down through stairs.

• 1 — the way in: stairs, ground
• → — the treasure lies this way

• 2 — a hole, 1 down
• → — the treasure lies this way

• 3 — a hole, 2 down
• → — the treasure lies this way

• 4 — stairs, 3 down
• → — the treasure lies this way

• 5 — stairs, 4 down
• → — the treasure lies this way

• 6 — stairs, 5 down
• → — the treasure lies this way

• 7 — stairs, 6 down
• → — the treasure lies this way

• 8 — stairs, 7 down
• → — the treasure lies this way

• 1 — the chest
• 2 — the chest
• 3 — the chest
• 4 — the chest
• 5 — the chest
• 6 — a tile to step on
• 7 — a tile to step on
• 8 — a tile to step on
• 9 — a tile to step on
• 10 — a tile to step on

The strongest 14 of 15 kinds whose nests reach this place.

There are 5 chests here under 5 quest numbers, so you can take them all.