Crossover Re: One; Forging (RE: Zero/TMSI) (Standalone spinoff)

A certain multiverse empire building 'ROB' family has its Emperor make a Really bad, No good, HORRIBLE mistake.

Subaru has a chance now.

But at what cost?

Join Subaru as he goes on a long road of invalidating his entire journey, appearing three years in the past in front of Kararagi to prove he can be taught by someone history supposedly forgot.