The Thunder Gem is a very violent gem, as it has no remorse whatsoever to who it attacks, whether the opponent is a Kayo Gem, civilian, or one of the captors. It has the ability to create massive and destructive thunderstorms which can either simply sting (think static electricity) or totally electrocute the target to death. It takes on the form of a large yellow thunderbird, which in this from, can cause thunder to strike from a screech, or a swift flap of the wings
Episode 13 was when Thunder appeared over Reidenton, the very day that Meilin returned from Hong Kong. It caused a lightning storm which triggered Ceaira's senses, causing the group to go after it. After Meilin brought it out from hiding Ceaira, Sakura, Li, Kero, and Yue combined their dark cards/gems/powers to stun Thunder so Ceaira could seal it. When summoned, it can create anything from a small shock, to a massive thunderstorm.
