A vengeful remnant
The Ottoman Empire was once the ruler of the world, but the new crusade has claimed Constantinople, and exiled the Sultan and his people to the searing deserts down South. Her Fearsome Majesty hoped that the struggles to survive in the plains of hot sand would burn out the Ottomans, but she underestimated them.
The Ottomans live by the rivers and oceans, where the temperature is a bit more temperate, and manufacture chemicals and optics, making use of the intense heat and sunlight of their new home. They fund the rebellions and supply them with contraband weaponry. One day, their Janissary corps will retake the holy land, and maybe, just maybe, set foot on the misty, mildewy, delicious streets of London.