How To Unlock and Use Blood Rage?

[Zero]

Yo Guys,
Alright so Zero is stuck here, I heard that Blood Rage gets unlocked after you play for a while, I'm already fighting the Soldiers and I really do not know if I have blood rage or not.. So I was wondering if anybody here knows how to unlock it or when it gets unlocked and how to use it after you get it, do you need any special blood art or weapon?

[Nekoyama]

Blood Rage get unlocked when you play some mission on Diffi 8

[jashinsamael]

The features unlocks as you progress, you even got a story training mission that cover how to use this.

and yes, it somewhere during dif 8

[Zero]

Thanks guys :)