[jutetrea]

Agree with Baalz and Velusion, I'll almost always try to get a small blood income going...even if its only a few slaves/turn. Make a few rods and have 1 or 2 sites going for a 5-20 slave income every turn. If its not part of the main strategy it adds up pretty quick.

Then it allows you to forge some really great items, blood stone being the primary. If you get a head start to const 8 you can nab some of the great artifacts as well.

I usually have blood spells as low priority, but bowl, toads and occasionally crossbreeding for chaff work well. If you've got the extra research, getting up to blood 6(?) gets you infernal disease (good assassin spell) and 5 gates (28 slaves for 5 demons in one cast). None of which are huge cost and potentially useful.

For moderate loss in income (and a bit more micro) you can get some pretty nifty benefits late mid-late game.