Lord of the banished

Basically an orc in the lord of the rings does an atriox and creates his own faction the banished.

You could do this in different ways, whether you make it so that atriox reincarnates as an orc or an si gains atriix's memories.

It could also be in other worlds like the Warhammer series, even 40k if you want to really push it.

Have fun with it.