Hm. I remember a setting for one I did on a website I now no longer visit. The RP for it was abandoned too.

But it was pretty much. So many people are vampires and an equal number are humans. The idea is pretty much as below.

Vampires control most of the world at night and are said to be the leaders. They operate sometimes at day too in special underground areas or fully light proof houses. Such as boarding them up and that. Humans are trying to remain themselves and don't want to join the vampires. They try to liberate areas every now and then during the day. When it is night they can either try and fight or hold up in an area. Only sunlight harms and kills vampires. The vampires played though can be full vampires who are a bit more powerful and have equipment for them to survive in the day. Like a hooded robe.

The more powerful vampires or ancestor vampires are not able to be killed in sunlight easily. They take damage from it but don't instantly die.

If you want to add on to that Seer. Feel free. It's the rough outlines of one I did. And it was good despite only having six people participate.

Terminal Damaged. Improbability Drive Disengaged.
Normality Restoration In Progress...
Keystone Fragment Compatibility Has Been Compromised.