Misa Ammane He acquired the Death Note when a Shirigami named Gelus sacrificed his own life to save Misa from an assassin.

Gelus was in love with Misa and watched her from the Shinigami Realm. Seeing that she was about to be murdered, he used his Death Note to kill the criminal, Breaking the supreme rule that Shinigami should not prolong human life, Gelus was punished by being turned to dust.

The delivery of the notebook: Another Shinigami named Rem, who witnessed the scene, took the notebook left by Gelus and delivered it to Misa on Earth, along with Gelus's remaining lifespan.