Tokofugu Cave

Tokofugu Cave (Japanese: 常冬の洞窟) is the fourth story dungeon in Izuna 1 and the first to use visibility as a gameplay mechanic. Dungeons such as Tokofugu Cave limit Izuna's line of sight to a set number of tiles in front of her while in corridors. This causes you to not be able to see monsters until they're standing on an adjacent tile from Izuna which can lead to them getting the first attack off if you're not cautious.

External Sources
English item names obtained from the GameFAQ's guide written by Matthew McIntyre. Used with permission.

Japanese monster names and HP/EXP. stats taken from the Japanese Izuna 1 wiki.

Monster spawn floors.