[Darkwind]

Well, two Enslave Minds is really good, and an essentially defenseless unit isn't. Without their attacks, I doubt the Brains deserve 500 gold, since a fairly high Astral power doesn't mean it's powerful enough for 500 gold. A unit that can Enslave Mind two enemies a turn, however, might (even though the two are essentially conflicting abilities). I'm not an expert, though (actually, I think it probably wouldn't deserve 500 gold anyways--that's a hefty cost for what's essentially a researcher that can double as a combat mage if it really needs to; seriously, 11 research per unit on a sacred, so it actually costs less upkeep than a mage Starspawn).