Power Stones

The Power Stones (パワーストーン Pawā Sutōn) are seven legendary stones that hold mysterious powers. A person that obtains three Power Stones can use Power Change, transforming into a powerful form for a limited time. In this form, the user is able to use Power Drive and Power Fusion attacks. Power Drive is the standard attack from the transformation. Power Fusion is more powerful, but consumes the transformation energy and can be used only a few times.

Besides the seven Power Stones, the first Power Stone game has a large Power Stone in Avalon Is. that has the power to make any wish come true, and in Power Stone 2 there is a large Power Stone under Dr. Erode's possession. However, the size of the large Power Stone in the end of the first game is inconsistent in some endings, appearing to be big in some images and fitting in the hand in others. It is possible that it can change its size.

Anime
In the anime a person only needs one Power Stone to use Power Change, but it appears that other Power Stones can't be used to transform after the first one used, thus each character has their own Power Stone. Like the games, there are seven Power Stones, with the addition of a Light Stone that appears when the seven Power Stones are together, a Dark Stone used by Valgas that is destroyed in the last episode, and several small black stones used by Valgas' Team that vanish when the user is defeated.