Polluted water from magic experiments has formed these caves and its noxious fumes have summoned the undead. A sluice gate was once installed to seal off the water, but it has since eroded over the years and now threatens to break completely, freeing the abominations that dwell there.
The Cave of Thackus is a dungeon in Valkyrie Profile, situated on the Southeastern coast of Midgard. It is a byproduct of the magical experiments in nearby Flenceburg, and the water that is dammed up inside threatens to pollute the entire shoreline. Some of the flooded sections inside the Cave are navigated with the help of lily pads. The dungeon is only available on Normal and Hard mode, from Chapter 4 onwards.
Lenneth ventures into the Cave to cleanse it of undead and finds the corpse of a sorcerer from Flenceburg who had come to renew the seal on the sluice gate, but fell prey to the creatures inside. His spirit tells Lenneth that she must hurry, and she finds the tools to renew the seal on his body. Before she is able to perform this operation, however, she must destroy the previous seal and defeat the mutated creatures in the polluted water. Once her task is complete, the sorcerer's spirit is able to fade away in peace.
- Eye of Heaven (explosion trap)
- Strike Edge (explosion trap)
- Flare Baselard (explosion trap)
- Bracelet of Zoe (artifact)
- Coin of Fortune (artifact)
- Monstrous Glowfly
- Mire Creeper
- Crab Giant
- Dragon Zombie
- Kraken and Crab Giant x3 - BOSS