Kamen Rider Kabuto 仮面ライダーカブト

Story:
The story revolves around a man named Souji Tendou. He has trained seven years while waiting for the Kabuto Zecter so that he may properly take up the name of Kamen Rider Kabuto. Making many enemies while at the same time meeting other Riders with mysterious origins of how they got there, Tendou attempts to accomplish his goal at all costs: destroying all Worms that otherwise threaten humanity. He meets Arata Kagami, who later becomes Kamen Rider Gatack, the two work together to save humanity from the alien Worms that arrived from a meteorite seven years ago.

Source: Wiki