Boss Cass got out on the wrong side of the egg. He didn't tiptoe around the shells either. He is infamously known as the first non-magpie to be elected Boss of the International League of Kleptomaniacs.
Ty the Tasmanian Tiger
His greed knows no limits as well as his distaste of mammals, and his latest coup had been the stealing of the Sacred Talismans that control the portal into the Dreamtime. With this, he would banish all mammals into the Dreamtime, and rule all of Australia.
Several years prior to the beginning of the story, while travelling in a Robo Fluffy, a giant robotic yowie or yeti, Boss Cass makes his way to Rainbow Cliffs to place the last talisman to open the portal to the Dreamtime. Before he could do so, a family of thylacines battled the would-be dictator cassowary, and seemingly won. But Cass activated the Fluffy to place the final talisman, activating the portal and sucking all the thylacines in. Luckily, one of the family members threw his boomerang to dislodge the talismans as he was drawn through the portal. In the process, this destroyed the portal and scattered the talismans throughout Australia.
To finish his goal, Cass sent out his army of reptiles to seek out the talismans and to prevent those who would dare stop him. Boss Cass even dispersed many despicable motives, such as sending his lizards out to reek havoc on innocent lives, damaging the enviroment, and even recruiting some creatures to do his bidding, even through sheer force. In the outback, a Frill finds the Tasmanian Tiger Talisman, and Boss Cass orders his minions to move out.
At his evil lair, Cass' Crest, word gets out that one of the talismans (the Frog Talisman, which was in Bull the razorback's possession) was retrieved by the last Tasmanian tiger, Ty. After receiving this message from Ty's long-lost brother, Sly the Tasmanian Tiger, who was adopted by Cass and learned his malign ways, the evil cassowary sends out his reptile minions to stop Ty. But failed to do so.
After Ty defeated Crikey, a tiger shark and King of the Coral Reefs who was cybernetically enslaved by Boss Cass, and retrieved the Platypus Talisman, the Frill and Blue Tongue leaders come to inform that Ty is "kinda well...uh...good." The Frill leader then suggests a surrender, which he was thinking. But an infuriated Cass reminds the Frill, through comical slaps and pecks, that he is the BOSS and he does all the thinking. He then tells the lizards to leave, kicking the Frill in the end. Sly decides to go and face Ty himself, for who knows Tasmanian tigers better than him. He does face Ty, but is for the first time ever beaten, but escapes.
Soon Ty finds the third talisman, being the Cockatoo Talisman, in the possession of Boss Cass' Robo Fluffy, which was given an artificial yeti skin. After the pelt is burned off, the robot is revealed to be piloted by one of Cass' henchmen, a female thorny devil, Fluffy. After Ty destroys the Robo Fluffy, the real Fluffy escapes, shortly after saying that if things were any different, she and Ty could have made a team. When Cass learns of Sly's failure, the villainous cassowary decides to let Ty retrieve the last two talismans (his and the Dingo Talisman), so that way he would use his most horrible creation to defeat Ty and steal back the talismans.
Ty reaches Cass' Crest and finds his girlfriend, Shazza the Dingo, with the Dingo Talisman. But before he can get it, another of Boss Cass' henchmen, Shadow the ghost bat captures both Shazza and the talisman, only to be defeated. Ty runs into Sly, and the two face off again, but Sly almost falls into a river of lava, only to be saved by Ty. Shocked by this Sly threatens Ty and runs off. Ty then enters a huge room, where he sees Boss Cass' ultimate creation, a gigantic super robotic yowie, Neo Fluffy X. As the robot marches out of Cass' Crest, Ty hops on, and faces Boss Cass in a final battle.
After weakening Neo Fluffy X, Ty is about to face Boss Cass, until Sly appears again. This time, he gives Ty the same boomerang the male thylacine (their father) lost after dislodging the talismans, the Doomerang; Sly had discovered that he is Ty's brother but just found himself on the wrong side. He wishes Ty the best of luck and disappears, angering Boss Cass further by the betrayal. With the Doomerang, Ty destroys the core of Neo Fluffy X, destroying it and all Boss Cass worked for. After Ty placed back the final talisman, the Tasmanian Tiger Talisman, he is happily reunited with his family. Boss Cass is then sent to Currawong Jail for his crimes.
Ty the Tasmanian Tiger 2: Bush Rescue
A year after his defeat, Boss Cass is released from Currawong Jail by Fluffy and her army of reptiles, just as Ty the Tasmanian Tiger and his team, called Bush Rescue, are about to stop them. Later on, the evil cassowary opens Cassopolis, a city for reptiles, and possesses diplomatic immunity, keeping him from being arrested as long as he is on 'Cassopolis business'. Little does anyone know, Boss Cass decides to pull a new scheme.
He sends Fluffy, who is now his new assistant after Sly's depature, to retrieve the Grid Processor from Currawong University. When Ty, who got a distress signal from Steele Springs, finds Fluffy there, she summons Patchy the Cybersaur (an Ankylosaurus with robotic enchancements on his head, tail, and back). Ty succeeds to defeat the dinosaur, but Fluffy escapes. She returns to Cassopolis with the Grid Processor, and Professor Karlos, a new henchman and evil uncle of Julius (a koala who works with Ty), places the processor into a horrible device called the Mammalian Manipulation Machine. As he activates it, the machine doesn't work. As revealed, Karlos still needs one more component. So Boss Cass sends Fluffy to retrieve another device: the Bio-Organic Micro Scanalyzer, which creates a holographic resonant image of the Deoxyribonucleic constituent of any tissue sample.
To cover her tracks, Fluffy starts a fire at an offshore oil rig. Ty, however, finds her, but soon faces another monster sent by her, Buster, a creature formed by the joining together of thousands of yellow bug-like nanobots, which is soon defeated by Ty. Back at Cassopolis, Boss Cass and Karlos once again begin another demonstration of the Mammalian Manipulation Machine. The machine starts with Bio-Organic Micro Scanalyzer extracting the genetic information from the mammal prisoner Cass captured, then the Grid Processor calculates the attributes necessary for the Frill subject. This mixes the warm-blooded strength from the koala with the Frill's cold-blooded ferocity to create Uber Frill. With test completed successfully, Boss Cass decides to put his evil plan into action: to kidnap the entire population of Burramudgee to create an unstoppable army of uber reptiles.
Fluffy then steals a Shadow Drive, but Ty defeats her and recovers it, along with a Data N.U.T., which after Julius analyzes it, everyone at Bush Rescue discover about Cass' diabolical plan. Before they can react, Boss Cass begins a seige on Bush Rescue HQ and kidnaps Burramudgee's citizens. Ty defeats the new Uber Frills, and soon he, Shazza, and Sly, who becomes part of the team, go to stop Boss Cass, along with Patchy and Buster. Ty faces Boss Cass once again in the heart of a volcano. Cass summons a swarm of green nanobots, which transform into a long-arm robot. But Ty destroys it, and defeats Boss Cass. The villainous cassowary is then seen back at Currawong Jail carrying out lunch duty and serving food to all of his lizard minions, saying in disgust, "This is so humiliating..."
Ty the Tasmanian Tiger 3: Night of the Quinkan
Boss Cass escapes from prison yet again. He meets with Ty the Tasmanian tiger at Cassopolis, where they decide to team-up to stop the Quinkan, a mysterious and evil force that is trying to take over not only the Dreamtime, but also the entire universe. Cass also tells Ty that he would figure out where Shazza is taken as she is captured by the Quinkan, if he would do some tasks for Cass. Ty's first job is to retrieve a thunder egg to power a machine to destroy the Quinkan, which he has to get by beating the Redback Gang in a racing derby. Then, his next job is to activate the emergency back-up generators for Cassopolis after the Quinkan destroy the others. The third job would be for Ty to keep a Robo Bug from being destroyed by the Quinkan at Cossie Atoll. And finally, Ty is to recover a device from one of Cass' drop ships that crashed on Kaka-boom Island. Ty discovers it was underwater, but faces a mutant hermit crab, which has used the ship as a shell. Ty defeats the crab and recovers the device.
Eventually, Cass comes good to his word and discovers that Shazza is being held hostage by a Dragonquin. Ty uses the Gunyip to defeat the beast and rescue Shazza afterwards.
Later on, when Ty faces the Quinking, the lord of the Quinkan and the main antagonist of the game, he finds the evil entity possessing Boss Cass. He reveals that Boss Cass foolishly summoned the Quinkan, believing that he would control them, only for them to use him as their unwilling pawn. The Quinking then takes the form of the most powerful being on the planet - Ty the Tasmanian tiger. After a long and staggering fight, Ty and the Quinking collapse in exhaustion. Boss Cass then appears with Fluffy, Shazza and Sly captured. To see to it he rules Australia, Cass has both Ty and the Quinking at gunpoint with a laser gun. Boss Cass, being a "sporting man", gives the two a sporting chance by firing on the count of three. As Boss Cass fires, Fluffy sacrifices herself to save Ty by taking the shot. Shocked and saddened for shooting Fluffy, Boss Cass is sent back to jail by Sly, too horrified to fight back. With Boss Cass back in prison and Fluffy remembered as a hero, Burramudgee returns to a state of peace with mammals and reptiles as allies, ending Boss Cass' evil for good.
Boss Cass is mean, arrogant, selfish, conceited and a bully who likes to exploit the frill and the blue tongue for his own good.