There are actually 6 BB spells, one for each region type:
*Each Spell can only be cast once on its corresponding terrain type. (this means if you already have a plains BB, you cannot cast another while it remains in your possession)
The Plains Black Between.
Minimum Fury: 125
Changes region into The Black Between - Plains -- can only be cast on regions you own.
"...the first fragment of the timeless tomb in my hands, I unleashed the secret words with a whisper. A gaseous darkness bubbled from the artifact with eerie life, the ground shuddered and heaved, and the voices of the dead sang their sorcerous song. Boulders and turf exploded and plunged into the void as we fled. Somehow, beyond reason or ritual, we escaped with our lives and a new, mystical ally: The Amra."
The Dunes Black Between.
Minimum Fury: 250
Changes region into The Black Between - Dunes -- can only be cast on regions you own."My chief commander, an Amra-rider, shrieked and clutched a gory stump as he fell headlong into the expanding pit. My legions scattered and ran amuck as the ground vanished into endless shadow...leaving only a swirling void where once tree and stone stood. I gave the artifact a second jolt of power, summoning our salvation from the supernatural distance. The Rip Lizards, a scaly lot known to serve only those with great sorcery, came striding forth and carried us to safety."
The Forest Black Between.
Minimum Fury: 500
Changes region into The Black Between - Forest -- can only be cast on regions you own."Deep in that dank cavern we came across a third fragment of the unspeakable Black Between. The moment I touched the glassy thing, a shivering, wet sound issued from the depths of the cave. A rotten stench filled our noses as my men began to cower from movement in the darkness. Somewhere beyond these stone walls, an entire region was being engulfed in nothingness...but here in this hole slimed, pinkish terrors emerged from ageless eggs to serve our sinister cause."
The Swamp Black Between.
Minimum Fury: 1000
Changes region into The Black Between - Swamp -- can only be cast on regions you own."...they were told to be the most gruesome of warriors, and the most formidable of foes. The Mud Wretches, a cursed people long ago transformed into twisted masses of bone and muck, refused to serve me until the Black Between was brought before them. I saw no leader, no throne room...only a bubbling howl beckoning me to cast the dark spell. I unleashed its fury, and from the brackish ground they rose...broken, dead limbs and cruel glassy eyeballs surrounded me..."
The Frozen Seas Black Between.
Minimum Fury: 2000
Changes region into The Black Between - Plains -- can only be cast on regions you own."The bizarre, translucent limbs of the Glows emerged ponderously from crag and chasm...bathing the fortress in a strange grey light. We had summoned one of them earlier within the keep's walls, but here they came in force. The Black Between was their master...for only the unspoken psychic powers of these elegant creatures can grasp the Between...just as only I could lead them to supreme victory."
The Mountain Black Between.
Minimum Fury: 4000
Changes region into The Black Between - Mountain -- can only be cast on regions you own."The moment was upon us. The final fragment would combine the conjunctional forces to at last open the gateway to the world of the Gods. Once opened, the door would allow one of the six great deities into material reality...if the summoner be one of evil soul, so will the world be consumed by death and suffering. If the final fragment be held by a righteous leader, then the infinite light of the kind Gods will redeem us all."