[rdonj]

Well, with tartarians the base cost to summon one is 10 gems. Then you generally have to GoR them for 20 more gems. This gets you a commander that probably has an affliction, is undead (giving it an additional weakness), and is insane. I believe some of them don't have all slots also. I would say that a naked mana spirit is quite a bit more useful than a naked tartarian. Then you also have to have either the chalice to heal them, gift of health, or a commander with healing. The chalice costs 40 gems, gift of health costs 50 to cast at minimum, and the faerie court spell costs 40 gems (while also being the least efficient method) if you don't have access to recruitable healers.

I could certainly see you losing some mana spirits unequipped, but even unequipped it is looking in my game like it would require mage power to bring one down. I am fighting vanheim at the moment, and I have a second mana spirit that doesn't have enough death magic to cast soul vortex naturally so I'm just using it on attack orders. It isn't invulnerable like the other one, but as a thug it's amazing.