Cayce was born to a family of farmers on the world of Keyorin, living a hard scrabble frontier life. Times were always tough through her first eight years, with little wealth and most of their produce going to the local warlords to secure their safety, until one bad season when her parents couldn't afford to feed their family and the local bands of criminals who preyed on them. The gangs arrived in force, and burnt their home, killing Cayce's father, and enslaving her and her mother. Before long, Cayce was on a shuttle headed for a meeting in high orbit with a slave trader, she would never see her mother again. Cayce was traded to a Trandoshan slaver who ran slaves to the arena on Nal Hutta. Most of the slaves were of little use to the Hutts, but vast quantities of them were thrown into the arenas as entertainment for the crowds to 'warm up' the gladiators. After arriving on Hutta, she was tossed into a group pen with a quantity of other random slaves from dozens of worlds, and forced to fight with the masses there for the few slops of food that were thrown in. She spent two weeks like that, fighting tooth and nail against larger oponents for a bite of food she would have thrown to the nerfs back home. This time impressed upon her the true nature of the world-- the strong thrive and the weak die. She saw those too weak to fight for their food starving in the corners of the pen, and so she made herself strong in mind, if not the strongest in body.
Then came the day that the pens were to be emptied into the arena for the entertainment of their bored Hutt owner. With the sun burning overhead, she was one of the first to immediately rush for a weapon once the doors into the field were opened, taking up a spear and a blaster, the later of which she tucked into her pants, and immediately charged at her chosen targets-- the weakest of the pens who she had been watching starve. She drove the spear into the skull of an elderly Bothan, and then whipped around to drive the butt of the weapon into the stomach of an Ithorian child who had attempted to enkindle a friendship between them. Dropping the weapon, she opened fire on the closest of her remaining targets with the pistol, who were still staggering towards the weapons, killing two, before a shadow loomed over her, and she turned to peer up at a giant man in green and black armor-- one of the first of the true gladiators.
The man was wearing a full faced helmet, but he wrapped his arms around her and yanked her to him, knocking the gun free and the wind out of her lungs. She heard his voice crackle from the helmet, as he whispered to her, "Stay calm, and work with me." He then opened up on the charging masses with his gauntlet flamethrower, killing six, and then charged forwards with a sword in one hand, and her wrapped in another. By the time that half an hour had passed, the mass of disposable slaves had died, and so had four other true Gladiators, all with her wrapped in one of his arms. When he finally staggered before the Hutt's floating dais, and raised his sword in salute, cheers sprung out of "Kata!" The Hutt laughed, and laughed, but then asked about the girl.
He was going to train her. The Hutt agreed, if he'd add five years onto his contract, and he agreed. The man named Kata, she'd find out was his clan name-- a dead clan-- was a Gladiator by choice of self-punishment, having been exiled forty one years prior by the Mandalorians for his service to the Death Watch during the Mandalorian Civil War. She was escorted into his quarters within the Hutt's palace, a large chamber, sparsely decorated with only a bed and private training equipment. For seven years, Cayce would train with Kata, and serve as his apprentice. He was an honorable man, but old and curmudgeonly, and had no patience for slacking, so she rarely tested his patience in her service to him, but in the ring, she was a cold eyed monster, who fought with ferocity. On her fifteenth birthday, he took her into the arena and sent her against a rival gladiator's apprentice in a match to the death.
She faced down a Rodian teenager in the ring, both wearing only their slave rags and the tabards of their collective masters. The Rodian wielded a pair of axes, while Cayce held her master's sword. They met in the center of the ring and Cayce darted to the side as one of the axes swung low to cut through one of her calfs, sending her to the ground. The Rodian let out an over-confidant cheer of victory and ran directly at her, and into her lifted sword, becoming impaled upon it. As her rival attempted to pull himself off of the sword, she released it, and picked up one of his fallen axes, burying it halfway into his skull. The Rodian died, and she was collected by Kata. Once the wound was handled, they walked into the sulferous swamps of Hutta to hunt and talk, where Kata taught her about the Mandalorian culture and religion and shared with her his Clan's secrets, and schooled her in the Resol'nare. When they returned to the Palace, five days later, Cayce Urriah had become Cayce Urriah Kata, a Mandalorian and daughter of Ruug Kata. They became a duo in the Arena, fighting side by side for years, until Ruug's contract ended, and he sought to leave the Hutt's service with his daughter.
The Hutt was only happy to let the old man go, but if he'd fight in one last retirement bout, he'd pay the man one million credits, for years of service. The duo agreed, and five days later, they re-entered the arena, which had been retrofitted with an overhead cage and electrified bars around the walls. The Hutt's majordomo announced the duo, and they stepped into the ring, only to be met by ten trained Gand findsmen who had been brought in for the event. The duo fouught back to back against the Gand's electrostaves and managed to kill them, despite taking heavy injuries. Then a Rodian entered the ring, followed by four others of his kind, the father and mentor of the gladiator who Cayce had killed during her first fight, and the rest of his clan. Ruug went down under the mass of swarming Rodians as he shielded the injured Cayce, with his body, five assorted bladed implements working beneath his armor plates and into his flesh. Cayce felt him go slack atop her, and saw the angry eyes of her enemies, so she lifted up her father's arm and flicked a switch on his gauntlet, firing off his flamethrower into the faces of their opponents.
When the Rodians fell to the floor, she staggered out from beneath her father, and into the opening door, where awaited the Hutt. His laughter boomed out, as she demanded her million credits, only to reply, "My deal was not with you." She staggered off into her father's old quarters to pass out from blood loss, only to wake up several hours later as a medical droid patched her up. She waited for several weeks to take an action, claiming her father's corpse and burying him with his armor in the swamps of Nal Hutta, only taking his gauntlets and one of his beskar pauldrons. Using a series of tools she'd pickpocketed throughout her childhood by patrons of the Hutt's palace, she hacked the doors into his security office-- killing the officer within, and used a data spike to give herself administrative access, re-targeting the turrets and security droids to anyone who wasn't a teenage girl-- her.
Explosions, blasterfire, and screams echoed throughout the palace, as she worked her way from room to room, killing anyone that hadn't already died to her machinations, until she reached the Hutt in his safe room. The doors opened for her, as she approached, and she raised up her father's micro-rocket launcher gauntlet towards him, and unloaded all of the ordinance into his bulbous form, turning, and leaving without a word. She worked her way to the landing yard, where several survivors were lifting away, fleeing in terror, and stalked the lot until she found a Dunelizard fighter, which she made off with, and left Hutt Space without so much as a middle finger raised into the air.
She hopped from planet to planet for a time, using newsfeeds and the holonet to figure out where the Mandalorians were, being the last of her Clan and the chieftain of said dead clan at the age of eighteen. For five years, she traveled the ass end of the galaxy, finding wayward Mandalorians who had lost their families in wars and on mercenary jobs, or to the Empire's invasion of Mand'alor, adopting a small corps of worthy men and women to fight alongside her, and maybe eventually re-take Manda'yaim.