Back in the dim mists of time known as the Pilot Season, the entity known as Kassil arrived on the Island amid the same confusion as all the others - pitched from a low-flying plane to crash into Newhome, naked and bewildered. This lasted but a short time, as the avid gamer took the the 'giant dungeon crawl' with an incredible degree of focus, eventually felling the Drive without help from the then-most-epic Clan on the Island, SWEET. His reincarnation as a Kittymorph left him somewhat bewildered, but he soon joined SWEET and became a somewhat active member, rampaging through the jungles vigorously.
This all changed when he first became a Joker.
One of the first few to be known as a Jokermorph, Kassil soon developed a phenomenal degree of apparent ability to manipulate space and time - entities who were nearly identical to him began cropping up all over the Island, each referring to the others as Timeshadows, which were all apparently instances of Kassil as he wandered through Four-space. This state persisted for quite some time, until, toward the end of the Pilot, he formed the Collateral Damage Adventuring Guild to house the most wildly chaotic specimens then on the Isle. He promptly reformed it after the Reset, although eventually he left it behind when he left the Island itself.
Cheshire Cat proved to be the undoing of the meta-temporal entity, as a portal into Fourspace caused it to collapse, violently evicting the various Potential Kassils into the nearest timeline - which, in the case of the Island, happened to land a Kassil who was from a timeline of technology that shifted into a semi-living, emergent state of being past a certain complexity. It was this Kassil who created Fish and gifted the clockwork flying fish to Skidge. Similarly, he created the Contraption, which has since apparently gone dormant somewhere in the Jungle.
Shortly thereafter, he vanished from the Island; some rumors indicated he had created a crude steam-powered boat and fled that way, while others swore they saw him vanish in a sparkle of green light. This came close to coinciding with the disappearance of Snickerer, of whom he had been a close friend.
Much time passed.
...And then, inexplicably, a human by the tagline of KVR arrived on the Island, looking nothing like Kassil the Jokermorph, save for a terrifying familiarity with the beasts of the Island and a knack for creating living clockwork devices. It took little time for him to flatten the Drive, reappearing as an all-too-familiar Kittymorph who promptly drew the attention of both Cadye and Skidge - the former recognizing his handiwork from the creatures he created as being that of the hands which had constructed Fish, while the latter recognized him for who he was and liberally coated Improbable Central in liquid glee.
He has since founded another Clan, Zenarchy, and seems to be formulating a plan to fix Fourspace - but apparently needs more Improbability and perhaps some willing aid to accomplish his goal.