009 - Mental Machine - Nightmare

Its nice for crowds in small rooms as well as single targets. It ties the grenade launcher for crowd control IMO. Just takes some getting used to with the timing and charging.

The Nightmare-Beta works in a weird way. It is powered off your Devil Trigger gauge. The more runes you have, the longer it retains its power. When your gauge runs out, the Nightmare-Beta will still work, albeit at a weaker strength.

When in human form, your runes work like "bullets". One (or several, if you like to charge your shots) can be expended per every time you use it. To get the most use out of it, use it in demon form. Damage is increased without using up your gauge to power it.