Time Chojin No. 2 and the bigger member of the Five Disasters. Like Lightning he is sly but focuses more on brute strength. He usually has the face of a lion and the clothes of a Greek Mythology soldier. His left shoulder guard, which resembles a lion's paw, can be used as a giant claw. His left hand can transform into the Legendary Destruction Bell, but it was destroyed by Geronimo's Apache Death Scream.
Not long after Chaos Avenir's sixth birthday, Lightning appears alongside Thunder in the Avenir Clan village.  They state that they resent being forbidden from using their Time Warp abilities, and proceed to attack the residents of the village, before attempting to murder Minutes Avenir with their Death Watch Branding. This was done in full view of Chaos, who clung to his mother. 
After Chaos' mother refuses to join them, they attempt murder upon her, too.  Chaos' mother and father tell Chaos to run, but - still alive - this tempts Lightning and Thunder to beat them to death. They decide to let Chaos run away out of the belief that he shall starve to death in the woods alone, now that his village and family have been eradicated. They don disguises and travel back in time to 1983, where they plan to kill all Justice Chojin. 
Thunder first appears alongside Lightning, during the Ultimate Chojin Tag Tournament. He can be seen reversing the clock, while the Justice Chojin train, and both snap off their horns in order to travel through time.  They appear in 1983 at the end of the Dream Chojin Tag Arc, and reveal themselves to be Time Chojin, who then attack Terryman - they proceed to defeat Terryman and Kinnikuman. 
They reveal that the New Generation have defeated all Evil Chojin, and even converted many to become Justice Chojin, and they blame the defeat of the older generation of Evil Chojin for the weakness of the new generation.  They seek to thus defeat the old Idol Chojin, so that the Evil Chojin of old will survive and prosper, and in turn the Evil of the New Generation will thrive. They ring the Legendary Destruction Bell, forcing the old generation to relive their worst traumas. 
It is revealed - due to not wearing his mask - that Robin Mask was not recognised by the bell, thus immune to the attack, and both attack Robin.  They then use Death Watch Branding to murder Robin Mask.  In the present day, Kevin Mask is slowly disappearing through time - it is revealed that Lightning and Thunder dropped their horns on the riverbank, which can be used to travel through time.  The Time Warp 8 arrive just at the moment of Robin's demise, and pry Lightning and Thunder away before they can complete their murder of him.  While the Old Generation are distracted and distrustful of the Time Warp 8, Lightning and Thunder try again to implement a Death Watch Branding.
Mantaro Kinniku runs to Robin's defence, but accidentally knocks Alisa Mackintosh into their attack, and Thunder and Lightning thus strike her with the Death Watch Branding.  Lightning and Thunder declare that the Time Warp 8 are their comrades, to further divide the Old Generation from the New Generation.  The Machineguns are unable to remove the trophy, at which point Thunder and Lightning declare that they should hold a new Tag Team Tournament.  They try to force the trophy from its place, but are severely injured, and they reveal that - when Harabote Muscle announces a new tag team tournament - was their intention from the start. 
The teams part ways to begin training for the new tournament. 
(More to Come)
Death Watch Branding
- Teams up with Lightning to murder their opponent
Triangle Thunder Choke
- Uses his legs - along with Lightning - to choke-hole his opponent
- Can turn his arm into a bell, which forces opponents to relive worst/traumatic memories
Win/Loss Record (Singles)
- O Robin Mask (Death Watch Branding)
- Laugh: Nuwanuwanuwa.