The display for Here Comes the Flood says the allies available is equal to the cards added (3x the locations, because each location gets a blessing, an ally, and a snake). However, that's not accurate. 8 sounds like a win for 4 characters. I believe the allies available are 3 + 2 + 2 + 1 + 1 + 0 for the locations an 6 for the cards added, or 15 allies total. And remember, allies that you fail to acquire don't count for either side.