Mt. Sekitoba was the highest peak on the Eastern Continent, and is mentioned in both Monster Rancher Explorer and Monster Rancher 4. The White Tower was built on it, and consequently survived the typhoon and is now known as Tower Island.
The only city nearby that survived and still thrives is the city of Sekitoba itself.
Given its mysterious history, it is no surprise that once Master Moo rises from the ocean, he makes this his place of residence, taking over the Tower and turning it into his fortress. In Monster Farm Lagoon, Tower Island is the eighteenth gameplay area, which you visit after Yutakinabar Island. The island has 11 Levels, leading to a showdown with Moo as he tries to return to full power.