Mount Iselina is an ancient mountain of Planet Zi. It is renowned for its thick fog, which has caused the locals locals to construct a myth about the presence of a "fog monster" on the mountain, which is actually just a reflection of the Zoids of travelers or from the villagers that live in the area.
Mt. Iselina is first shown in the Zoids: Chaotic Century anime series, primarily in episode 11. There is a remote village on the mountain. Major events are as follows:
Van and Co. try to traverse it as part of their journey, but Irvine and Fiona get separated from Moonbay and Van, after Van hallucinates about flying Papayas.
Van meets with Rosa, who invites him up to her village, a very remote village settled on the mountain.
Viola chases Van and tries to defeat him, but is defeated due to Rosa's actions.
Viola is revealed to be Rosa's sister, and is from Mt. Iselina herself.