Fate\Stay Night X Re: Zero Crossover Challenge
When Pack decides to unlock Subaru's gate, something else also awakens within him (Subaru), like an old machine was finally switched on after many years of disuse. After this occurs, Subaru finds himself plagued with visions of battles, humans with superhuman abilities, a golden chalice tainted with black mud spewing from it, a dark-skinned man with silver hair wielding two short swords and four pairs of hands warmly reaching out to him. As time progresses, Subaru starts displaying skills that he previously did not possess. Now armed with new abilities, Subaru vows to save everyone. But will he be able to become a hero of justice or will his new (?) ideology betray him. Also, it seems that there is more to Satella and Echidna than previously known. One would harm him for saying too much and the other seems to have a love/hate personality towards him, now they brutally destroy anyone who hurts him regardless of past friendships, age or gender. What are the real identities of the Witch of Envy and the Witch of Greed and why do they call him Shirou?
NB:
To confirm, yes Subaru is Shirou Emiya reborn, Satella is actually Dark Sakura (or normal Sakura. Your choice) and Echidna is Illya.
This should take place after the bad ending of F/SN Heaven's Feel.
Because Shirou's mind was broken in the bad ending, Subaru will receive fragments of memories and will be unable to access the full power of his tracing ability due to damaged circuits.
To clarify, After Dark Sakura wins the war, she uses the grail to amplify her powers and spread the shadow across the world. After a couple hundred years (you can choose how many), her old personality starts to surface. Eventually it is able to wrestle control and order Saber Alter to kill her (Who fades due to having no master to give her prana. Also Sakura cannot use her own powers to kill herself so she needs a divine weapon, Excalibur Morgan, while tainted is still a divine blade). The souls of Sakura, Shirou, Illya and Rin are able to avoid the Throne of Heroes and reincarnate.
You can choose who Rin will be reincarnated as.
Illya hates Shirou for taking Kiritsugu from her but grows to love him after spending time with him. This can translate into Echidna's love/hate personality as she does not have access to all of Illya's memories.
You do not have to follow all of these as they are simply thoughts and ideas. (Except for 1 and 6)
This challenge is based off of Boyzilla's Re: Circuits fic.