How to take third vampire lord in five easy steps:
1-Find isolated village of humies/goblin camp!
2-OMNONOMNOMONOM all night long!
2b-Remember to be triggering Create Spawn!
3-Make sure to leave enough survivors to perform the necessary funeral services (or bury them yourself you lazy bastard, you don't tire)
4-?
5-Profit!
Basically, you just need to create spawns, you don't need to control them or even hang around until they return. If you're in an hurry, an orgy of blood is a perfectly viable solution. After all, what kind of lousy vampire wants to be a lord but can't even corrupt a village?