At what point do you realize that this is a film about vampires? What are the clues?

The film begins in 1536 with an alchemist creating a device that will give him eternal life. 400 years later we see the scene of a tragic accident where a vault had collapsed, one of the deceased was the alchemist, who had been pierced through the heart with a wood stake. His skin appears strange, non-human and a marble white color. At the alchemist's mansion is discovered blood being drained from a dead corpse. The cronos, which the alchemist created for eternal life is not documented in the sale of all of his possessions, including his home, and the basins of blood discovered in the home were never revealed to the public.