At the end of the war, after Gilgamesh's defeat, Shiro orders Saber to destroy the grail, however, the grail triggered an explosion that drew in all the masters(mostly the originally masters) of the war, Shirou, Rin, Sakura, Illya, Bazett, and Kuzuki, along with there servants from the grail. They end up in Earthland, the heroic spirits notice a clear change, Pure and bountiful mana filling the world, as well as magic core developing in their masters, as well as a clear difference in how the magic worked, not requiring mystery, not even originating from mystery. Even changes in themselves, Berserker could talk normally for Pete's sake, And Saber somehow released somekind of magic Roar on that perverted monkey thing.

Magic: Shirou(requip, blade memory make(the weapons are actual blades, not just projections)), Artoria(requip, Red Dragon slayer magic), Rin(magic rings), EMIYA(requip, Blade memory make) Sakura(card magic), Medusa(stone eyes, Summoning/takeover(Pegasus/gorgon), requip), Illya(Wire magic, Celestial spirit magic), Heracles(requip, Takeover(Beast soul, the monsters hes most famous for beating)), Bazett(rune and requip), Cu(requip, speed, runes), Kuzuki(body empowerment magic, gun magic, shadow magic), Medea(what ever the fuck works), Sasaki(requip, Speed)

Heracles is more human looking now. Artoria's dragon magic core basically a dragon lacrima. Kuzuki is a former assassin.

The servants of the war are now proper humans/demigods.

Red 'celestial spirit' keys for heroic spirits. Shirou with Mordred, Morgana, and Kiyohime, guy just can't get a break.