Just a quick note on a little thing I have been doing to make my prayers/spells/etc. feel more Luciferian–

I never really resonated with “Amen” or “So mote it be.”

Thankfully, Paradise Lost provided me with an alternative. When Lucifer/Satan surveys his new domain (hell), Milton has him proclaim: 

Is this the Region, this the Soil, the Clime,
Said then the lost Arch-Angel, this the seat
That we must change for Heav’n, this mournful gloom
For that celestial light? Be it so, since he
Who now is Sovran can dispose and bid
What shall be right: fardest from him is best
Whom reason hath equald, force hath made supream
Above his equals. Farewel happy Fields
Where Joy for ever dwells: Hail horrours, hail
Infernal world, and thou profoundest Hell
Receive thy new Possessor: One who brings
A mind not to be chang’d by Place or Time.
The mind is its own place, and in it self
Can make a Heav’n of Hell, a Hell of Heav’n.

Yes, it’s from poetry, not a magical text or “real” scripture, but “Be it so” is pretty much exactly the same as “So mote it be” but with a more specifically Satanic/Luciferian flavor.