[mindlar]

I was looking at the prices for some of the blood summons and was confused by the prices of some of the spells.

Bind Fiend costs 2, Bind Devil costs 3, Bind Frost Fiend costs 2, Bind Storm Demon costs 3, Bind Demon Knight costs 5. Ritual of Five Gates costs 28 slaves (13 more than the individual summons), requires 3 more blood than the individual summons, and requires 2 more levels of research.

I'm sure there is a reason that Ritual of Five Gates costs almost twice as many blood slaves as the individual summons, but I can't think of any other than the reduced amount of mage time required.

A similar issue arises with the level 9 spells: Infernal Forces (50 blood slaves for 7+ devils), Infernal Tempest (50 blood for 7+ storm demons), Forces of Ice (50 blood for 8+ frost fiends), Forces of Darkness (50 blood for 14+ fiends). Infernal Crusade (50 blood for 10+ knights) is the only one which potentially presents a cost savings.