Kamen Rider Kuuga.

When a group of archaeologists uncover the tomb of a legendary warrior, they unearth Kuuga’s belt, accidentally releasing an ancient race of monsters called the Grongi, bent on destroying humanity. Enter Yusuke Godai, a modern-day guy next door, who learns he is telepathically linked to the mysterious stone belt. With its power, he transforms into the legendary warrior known as Kuuga, humanity’s only defense against the murderous Grongi monsters.