He is a mercenary. He has a big space ship and keeps getting jobs from Mumm-Ra to fight the Thundercats. He is very expensive. Despite being a bad guy he seems to have some kind of code of honor. Fortunately, it doesn't get in the way of business.
Captain Shiner's Guards
What's a captain without a crew?
Captain Cracker
A loony robot pirate captain. He sails around space doing what pirates do (plunder, pillage, etc). He tried to defeat the Thundercats on several occasions.
Polly
Captain Cracker's not-so-loyal companion. Sits on his shoulder most of the time and acts like a parrot.
Captain Cracker's Guards
Low level intelligence robots that Captain Cracker commands.
Grune, The Destroyer
An ex-Thundercat that was banished from Thundera. He is now dead, but his ghost lives on. He pops up every now and then to give the Thundercats a hard time.
Burn Out
Just some really bad nearly indistructable robot that goes around ripping up the landscape.
Plutar
This interstellar baddie should offer his services as a professional weed killer. Everything he touches withers and dies. If he "takes root" into a planet, the whole planet dies.
Energy Bat
Safari Joe used the energy bat to attack Panthro.
Frogman
A humanoidish frog guy that has the abilities of a frog. He also has some neat weapons. He is currently banished in an underground water prison.
The Mirror Wraith
This weirdo lives in a mirror dimension. He can enter it through one mirror and exit through another. He can be defeated if all the mirrors are covered.
Baron Task
This dude has a fixed system where anyone who works for him to pay debts goes deeper in debt over time. He knows about the Well of Doubt. He has a magic amulet that controls two stone statues.
Mr. Grubber
Baron Task's accountaint. Balances the books so people owe Baron Task more money. He's a wimp and couldn't be a bad guy without the baron.
Shadowmaster
This guy was banished way back when, before Thundera blew up. He has great magical powers and imprisoned Claudis.
Two Time
A robot with four arms, four legs, or any combination with a total limb count of four. Some people say two heads are better than one, but for this guy all it means is being upside down and rightside up at the same time. He can alter the personal gravity of someone.
Safari Joe
An intergalactic sportsman. He finds out his prey's weakness then uses weapons to utilize the weakness and defeat his opponent. He has no honor and is a dangerous foe. He has some cunning but not quite enough.
The Ninja
Mum-Ra summoned him to fight Hachiman and the Thundercats and to also rescue Slithe.
Kibera
This evil race of aliens are out to destroy the Territors. While they may look peaceful (or at least not as hostile as the Territors), the are evil and not to be trusted.
Malcar
He is an evil alchemist. Mumm-Ra raised him from the dead so he could turn thundrillium into thundrainium. He uses the Alchemist's Stone to transmutate matter.