We’re still working on the text, art and layout for the beastiary. In the meantime, its worth mentioning the following conversion rules from old-school monsters to EoF:

Defense = (15 - AC) or (AAC - 4)
Health  = 6 + (6 * HD)
Attack  = Roll + (25 - THAC0)
Mana    = (HD * 3)

and the difficulties table for challenge rolls:

DIFFICULTY             	 ROLL TARGET
====================================
Non-trivial            	 7
Significant challenge    11
Extremely difficult    	 15
Virtually impossible     19
Are you serious?         23
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If the character has an advantage or the player has a good plan or strategy, apply a -1 or -2 modifier to the challenge roll target.

If the character has a disadvantage or the player has no good plan or explanation, apply a +1 or +2 modifier to the challenge roll target.