Nocticism

Vampirism is both a religion and a way of life. Anyone can become a vampire, and they don't need to abandon their current religion to become one. Vampires are immortal beings, they have eternal youth and strength, but they are not unkillable. Vampires believe in the goddes of night Nyx (also sometimes referred to as Lilith). She is the one who gives them their immortality and the one who powers bloodthirst. The process of becoming a vampire starts by drinking the Elixir of Life. After that, the person may experience Heliophobia, intense outbursts of violence and increased nightly activities. After that period has passed, the person who drank the Elixir officially becomes a child of the night. When becoming a vampire, you don't need to abandon your current religion as mother Nyx doesn't deem other gods less worthy or important. Not every vampire is violent. Some prefer to only drink the Elixir instead of killing, however the Elixir may cause them to temporarily become bloodthirsty. A vampire will also never kill another vampire for blood.