Crominus has a golden armour accessory with a transparent flat blue stud, which represents Chi. He has a red torn up cape. His head mould is gold on top and olive green printed on the bottom with lots of crooked teeth with reptilian scales. His arms are olive green but his hands are dark green. His torso is scaly with muscles and red ripped cloth and in the middle of his torso there is a circle of chi. He has printings of a red cloth continuing onto his legs, except with white bones connected to it. The bottom of his feet are printed with claws.
Crominus' appearance in the TV series is identical to his appearance in the sets, except he has a grey goatee in the TV series. His crown is also a little more gold and shiny.
King Crominus is the leader of the Crocodile tribe and is married to Queen Crunket. King Crominus never saw eye-to-eye the Lion tribe, however, he had enough common sense and respect to never begin open conflict with them. Cragger is their son, the prince of the Crocodile tribe, and best friends with lion prince Laval. In a war between the lions and crocodiles, King Crominus and Queen Crunket later fell down into a giant sinkhole inside their tank, causing Cragger to become the ruler of the tribe. According to his wife Queen Crunket the Gorge of Eternal Depth has a gravity field that broke their fall. The caves lead to the Outlands where Crominus has been imprisoned.
Around the time the outlands team rescued him, it was revealed by Lavertus(to Rinona) that Crominus and Lavertus had a grudge to settle which prevented Lavertus from joining the fight. Crominus and Lavertus both loved Crunket, but Crunket loved Lavertus. Crominus had forced Lavertus to steal CHI using the persuader plant, therefore the lion was exiled and Crominus was clear to marry Crunket. Lavertus and Crominus later confronted each other, Lavertus gaining closure and Crominus feeling even worse about his crime. Lavertus then accepted fate and told him that if he had not married Crunket, Cragger, a great hero, would never be born, before Lavertus sacrifices himself. Crominus returned with the others to Chima, sharing his story and offering himself in servitude to Lavertus to make up for his crime. The offer was denied and Crominus remains king of the crocodiles.
Crominus was later frozen when the ice hunters launched their attack on the crocodile tribe. He now resides in Fangar's trophy room, before being freed in A very slippery slope.