Misa Amane discovers Light Yagami's identity as Kira in the anime "Death Note" through a series of events. She first becomes suspicious of Light when she sees him acting in a way that reminds her of Kira. Later on, she confirms her suspicions when she touches the Death Note and regains her memories of being the Second Kira. This leads her to directly confront Light and reveal that she knows his true identity as Kira.
