There is a broad agreement that Urshifu is an extremely powerful pokemon – the guardian of the Isle of Armor, who will someday protect that isle from the Darkest Day or the end of the world – but that's where the agreement ends; how it does so is the topic of the island's oldest dispute. Some texts describe it as a red bear who shall defeat Eternatus and its Dynamax army in a single strike, others as a blue beast who rains down a rapid flurry of blows on Eternatus' minions before finally wearing down its ultimate foe.
The controversy, as with all eschatological ones, is incredibly divisive – for choosing wrong could doom the world. Each faction is based in its own stronghold, and while both still stand, their fortifications of the Tower of Water and Tower of Darkness testify to the bitterness of their stalemate. In theory, it is good for a population of Urshifu to be trained in both tactics, so that whichever works will have an elite representative; in practice, the use of Houndoom with Single Strike Urshifu left them considered by their rivals to be natural allies with the armies of hell, and Inteleon's reputation for dirty fighting left "Rapid Strike" synonymous with "cheating". Rapid Strike advocates countered that, if it was cheating, then cheating was worth it to save the world, but the Single Strike faction solemnly retorted that "one can not cheat Eternatus."
Although the acolytes of both fighting styles have given up on trying to destroy the other, they still fiercely compete to lure Kubfu on the brink of evolution into their towers, in the hope that this one will be the Great Urshifu who saves the Isle of Armor – and perhaps even saves the world.