An ancient God called Ranga awakens on an isolated island in the South Pacific where it has been slumbering forgotten by mankind. Three sisters living in Tokyo—Minami, Ushio, and Yuuhi Shimabara—discover they have inherited this Island Kingdom, along with the huge God. When Ranga shows up in Tokyo, it soon becomes a source of wonder and conflict for the three sisters that control Ranga, the people who want to destroy it, and ones who want to use it. (Source: ANN)

Kaibutsu-kun and his companions, Dracula, Wolfman, and Franken, travel from Kaibutsu Land to the Human Realm, where they encounter and battle several monsters, mainly assassins from the demon group Demonish. (Source: Wikipedia)

The age of the demons has begun. Dr Faust has foreseen this rise of evil. Unfortunately, he is near death and is unable to personally battle this upcoming threat. Faust entrusts a young boy, Shingo Yamada, to take the responsibility of ridding the Earth of this new evil presence. Faust finds a birthmark on Shingo's forehead that signifies that he is the chosen demon fighter. Faust summons from hell what may be humanity's only hope of surviving: a less than enthusiastic devil named Mephisto rises. After signing a pact in blood to save humankind, Shingo and Mephisto set out to battle the supernatural world. (Source: AniDB)