Vesper Cave

First mentioned in Day 161.

One of the higher difficulty dungeons in the Labyrinth City [Purgatory].

It's a cave dungeon that has a structure similar to an ant's nest.

The cave's rock walls were damp, which caused them to reflect the light in strange ways. There were many pools of water on the uneven floor that could be an unexpected obstacle while fighting, as well. The temperature was lower than expected, causing our breath to become visible. We were able to hear the sound of flowing water if we listened carefully, as even small sounds echoed off the rock walls.

Because of the many water-based traps in the dungeon, adventurers need to prepare waterproof gear to protect against the cold in advance. Light sources include the light moss growing here and there on the surface of the rocks, though the light was very dim.

Many of the monster types that appear here use the basic terrain to launch surprise attacks on adventurers, though some are powerful species that are very tough, as well.

Some of these monsters include: As expected of this terrain, a lot of the monsters have abilities that use the water and ice attributes.
 * "Aqua Slime," a Slime that looks like the water puddles around it at a glance.
 * "Water Strider," a creature that shoots water from its mouth like a bullet.
 * "Poison Cave Lizard," a Lizardman whose claws and fangs contain a powerful poison.
 * "Red King Crab," a huge crab that is the size of an ogre and is clad in a hard shell that's stronger than steel.
 * "Cave Alligator," a Gatorman with the head of a gator and the body of a human. It can make full use of the variety of weapons that it possesses.
 * "Assassin Bat," a bat that uses ultrasonic waves to attack from the darkness with its wing blades, which can cause negative ailments.
 * "Aqua Elemental," a monster that can manipulate water. Its body is made of water that has gathered around a metallic core, giving it a similar appearance to a Slime, except that it floats in the air.
 * "Thunder Hog," a monster that fires lightning attacks from the countless needles on its back.
 * "Earthshaker," a creature similar to a catfish that uses its long whiskers to manipulate electricity and the earth.
 * And so on...

Some monsters appear to make use of the lightning attribute.

By the way, the Red King Crab is the strongest among them.