[Endoperez]

There are a few Blood sites, even though the Damned Merchant might be the only one that produces Blood Slaves. Demon Gate, Blood mage may enter to summon Devils (the Fire type), and another that allows summoning of Fiends of Darkness... and of course Brigands' Lair or whatever the 0-level site is. Any mage, or even a priest, searching for sites finds it, because it's 0-level site, though.