It's terrible though if several of your doctors, carrying a bunch of dangerous dragons or phoenixes, are taken down. Then you have to destroy the band of creatures a second time and summon the doctors again. Shrines don't regenerate your mana as quickly as 'liths, but they definitely play an important role in Sacrifice, especially on the larger maps. Converting fallen foes occurs faster and your sac doctors don't have to undertake the dangerous journey back to your altar. You shouldn't need more than one as long as it is strategically placed far from your own altar and near a location where you'll slay many foes.
Nothing is accomplished quickly in the game and most of the missions are battles of attrition.
Take small steps to controlling the soul population and manaliths, working towards an enemy wizard's altar. When two are attacking, focus on one and then the other. It's too easy to begin thinking the game is impossible when it isn't. There are just definite battles you can win and ones you will always lose so choose wisely. As the game progresses, you obtain the powerful long-distance ranged units.