Ritsuka has been dreaming of a mysterious swordsman of red armor and long blonde hair since the day she picked up a red and white trinket. Now, with Human History incinerated, that same fallen hero will help her overcome that ordeal. How? WITH MEGAMERGE!

I always knew I was 'born' different from other people the moment I opened my eyes in that hospital.

The Class Cards weren't the only ones to enter that world. Other artifacts with the power of legendary heroes known as Biometals are now present in Fuyuki, each choosing hosts of their own! Will Illya and Miyu convince the Mega Men to fight for love and justice or will the Chosen Ones cause even more havoc than the corrupted Heroic Spirits?

Shirou accidentally summons a "Legendary Hero" Saber to his rescue! Except this Saber never cared about justice and doesn't recall ever calling himself a hero...

Enzan is bored, while Netto is chased by his own bad luck. What comes over the two are something much more complicated: The Holy Grail War.