[Aleph]

You can definitely triple up on rain of toads to instakill an enemy's unit production, severely hurt gold productions, and slam them with misfortune (which may cause further economic chaos). That's what, 12 blood slaves for all that? Granted, you need three people who can cast it, which makes for a fairly short list of armies outside of Mictlan and Lanka (Sauro, maybe?), but if that doesn't make the good list of offensive rituals I don't know what does. The 3 chances to disease enemy units is just added frosting. Rating: As good as it gets.

As far as attack spells go, to continue with the blood theme Infernal Disease is a bargain - 5 blood slaves kills almost any commander that's heavily protected, and even the exceptionally tough almost always still end up diseased. Rating: Good.

Send Horror in its various forms really needs to be cast multiple times on the same enemy army to pay off, but 2-3 of them can usually rout an enemy army even without getting lucky and shredding a commander, and they can also jack up an enemy pretender with horror marks. I'd say they are not as efficient as the preceding two, though, since they may not end up inflicting that many casualties before routing the enemy, and don't work well in offensive siege warfare. Rating: OK - not a great spell most times, but sometimes exceptionally useful in counter sieging when you've cut off all escape routes but can't defeat the sieging force.