Pretty sure this is a Chinese Drama. It’s a historical fantasy piece. The female lead was found floating in the river as a baby, everyone but the village chief wanted to throw her back into the water. The chief raised her with his own daughter. Every year the village has a ceremony to see if one of the four gods has been reborn into a girl. They do this by dropping blood onto some stone. The female lead has always been banned from participating but this year her sister sneaks her in. Both sisters turn out to have one of the four gods in them.
The factions start fighting over who is more powerful after that.