Kastore was a regnant elven sorcerer hailing from the world of Terra, who went on to partake in the exploits of Corak the Mysterious, later reaching the world of Enroth where he assumed a new role as King of Deyja. His goal as King, the restoration of the Heavenly Forge, ultimately failed, and his fate afterwards was unclear.
Born on the oceanic planet of Terra, Kastore became a Sorcerer attuned to Cosmonium in his early life. Other details about his past are not expanded upon, but during his relative youth, in 491 of the Terra calendar, he became one of of the eight adventurers destined to encounter Corak the Mysterious and aid him in his battles against the fallen Guardian, Sheltem the Dark. Kastore's seven comrades included Crag Hack, Dark Shade, Maximus, Resurrectra, Robert the Wise, Sir Caneghem and Tolberti. The band had apparently gathered together to search for a means of reaching the Ancients, the beings who colonised the nacelle worlds and biospheres in ages past.
After traversing most of the landscape of the isles of Terra, abating the land's three kings and attaining the title of Ultimate Adventurers of Terra, Kastore and his band encountered Corak battling with Sheltem himself inside the Ancients' original Terran colonisation ship, the Shikbath Zera. Evenly matched, the two Guardians fought until Sheltem saw fit to depart in a nearby escape pod.
Corak pursued in another after giving the eight adventurers quick instructions on how to pilot a third pod - the starship Lincoln. Corak had done so in the hopes that they would successfully land on the nacelle world of XEEN and continue assisting him there. Unfortunately for Corak, the eight adventurers drifted off course and hurtled towards the world of Enroth, another planet in the Spinward Rim.
Kastore and Resurrectra each held a part of the password to the Lincoln's security system, and agreed to "hide" the Lincoln in the shoals at Brighton Point, west of the Elven lands of AvLee upon the continent of Antagarich. Equipped with high-tech wetsuits and Control Cubes, the eight adventurers embarked onto dry land just as a skirmish ensued between Deyjan armies under Archibald Ironfist and Gavin Magnus's Bracadan scouts. The adventurers' startling appearance frightened off the battle's remaining survivors.
Upon the beach, the adventurers argued over their next course of action. Kastore, Dark Shade, Maximus and Tolberti wished to pursue the Deyjans, while the other four sought to follow the AvLee forces. After a bitter argument, the two groups seperated, Kastore the leader of one and Resurrectra the leader of the other.
Kastore and his three comrades made their way to Deyja where they became advisors to King Archibald. Learning more about Enroth over time, they discovered legends about the so-called "Heavenly Forge", a technological device used to produce Ancient weapons. Eventually, Kastore managed to overthrow Archibald - who was more interested in necromancy than technology - and became the last known King of Deyja.
However, Resurrectra's group obtained the Oscillation Overthruster (a crucial component to reviving Ancient technology) and used it to revive The Gate, a portal to a space-station leading to a myriad of worlds. Following this event, Kastore and his allies were not heard of again and made no appearance following the Reckoning, though are presumably still alive.
- Kastore almost certainly had a role in the original concept of Heroes of Might and Magic III: Armageddon's Blade, which was planned to feature the Heavenly Forge faction with the Dark ending of Might and Magic VII canonical. However, because the Forge was opposed by fans and removed, he is neither present nor mentioned whatsoever in the game.
- A character named Kastore appears as a playable Warlock hero in Heroes I and II, utilizing the portrait of Seymour from World of Xeen. His presence here is non-canonical, as the Ultimate Adventurers did not reach Enroth until a decade after the game's events. Although, it is also likely that this is an entirely different Kastore, much like the second Crag Hack to appear along with the Ultimate Adventurers.
- Kastore underwent a major design overhaul in his progression from Might and Magic III to Might and Magic VII. In the former, his portrait appears as a simple blue-skinned elf. In the latter, his full body can be seen - his skin colour has been changed to pale and he wears arcane, Ancient-style armour. The same change in complexion is evident in Corak, another returning character in Might and Magic VII from the earlier quintology, and likely just a result of improved graphical capabilities.
- In Might and Magic VII, Kastore claims to the Deyjans that the Ancients are a myth and never existed. Unless he was simply attempting to manipulate them, one wonders how else he can explain the origin of the blasters, seedships and the Forge, all of which he himself had encountered firsthand.
- Kastore's name is a play on words relating to his profession, a "caster".
- While in Might and Magic VII Kastore is shown as an evil elf, his alignment in Might and Magic III is neutral.