Loss of Memory （ 記憶の消失 / きおくのしょうしつ / kioku no shoushitsu ) is the fourth chapter of the Elfen Lied manga series.
Kouta and Nyu watch as Yuka is knocked out by Bando, who laughs, as Nyu's horns confirm her identity beyond any doubt. As Kouta tries to tend to the fallen Yuka, Bando demands to know who he is, and when Kouta tries to avoid answering, he's knocked unconscious in front of a horrified Nyu. Bored with his conquest of the pair, Bando arrogantly declares the action self-defense, and wonders why Nyu is trembling, which belies her reputation as a vicious killer. Satou tries to remind him of the two-meter rule, in regards to approaching Lucy, but he brushes it off and strikes Nyu when she turns her attentions to Kouta.
All of his taunts and blows can't seem to get a rise out of her, which disgusts him, as he had been itching for the fight he thought Lucy could provide. Striking her for the final time, he orders a stunned Satou to kill her. After some deep reluctance and a refusal by Bando to consider other options, Satou apologizes to her and appears to fire his gun pointed towards her head.
Kouta wakes up on the beach to find a group of paramedics tending to himself and Yuka. Yuka is found only to have minor injuries. In the hospital, his story of being attacked by armed masked men is met with disbelief by the police, as is his claim that another girl other than Yuka was present at the scene. The police tell him his "muddled" memories are from amnesia caused by his injuries. Growing suspicious when they quietly urge him to forget all about the attack, Kouta withholds information from them regarding Nyu's appearance. On the cab ride back to Maple House from the hospital, he and Yuka chat about the missing Nyu, and Kouta's suspicions about the situation only go deeper. After being dropped off at his new home, Kouta watches the cab drive off. Once inside, he again eyes the shell that Nyu snapped in half, which was, at that point, the only proof she was ever there at all.
- The chapter cover image features a topless Lucy (censored here to meet Wikia's Terms Of Service) leaning forward with the ahoge at the top of her head. This piece of hair would eventually be phased out of her character design.