Riku first met Naminé in Castle Oblivion. Vexen had created a replica of him and forced her to give him fake memories. However, Naminé also met the real Riku. She first appeared to him in the form of Kairi and assured him that he would not be destroyed by the light or the darkness and that he should accept both. Afterwards, Riku decides to go and look for Naminé, especially after DiZ tells him that he must choose between the light and the darkness.
Riku later found Naminé and discovered that Sora was sleeping inside of a pod. He said that he told Sora to take care of Kairi and complained that he was taking a nap instead. Naminé offered to seal away the darkness inside of Riku that was at risk of corrupting him again, but he decided that it was better to face that darkness instead. He decides that he must face it himself and she is satisfied with his answer. Riku then notes that Naminé and Kairi smell the same.
As the days pass of Naminé reconstructing Sora's memories, Xion's presence begins to interfere with this. Riku talks to her about this and decided to help Xion when she wants to learn the truth. After Xion merges back with him and Roxas is placed in the simulated Twilight Town, Riku is tasked with watching over Roxas and Naminé as Sora's memories are restored. Naminé attempts to speak with Roxas multiple times but Riku stops them because DiZ orders him to.
After Sora's memories are restored, DiZ orders Riku to destroy Naminé. He refuses and ends up helping her escape with Axel instead. At a later point in time, Kairi is captured by Organization XIII and imprisoned in the Castle that Never Was. Naminé and Riku worked together to save her and keep her safe. After Riku returned to his normal self and was unable to open corridors of darkness, Naminé appeared and opened a corridor so that everybody may return home.
RikuNami as a decent amount of popularity in the Kingdom Hearts fandom. It is not as popular as Soriku, RiKai or RokuNami but is still has quite a few fans. This was especially the case throughout Kingdom Hearts: Chain of Memories. Since Sora already had Kairi, many fans shipped Riku with Naminé so that everybody would have somebody. However, things changed once Kingdom Hearts II was released and it was implied that Naminé was a love interest for Roxas instead. However, some fans have still latched on to the idea of her being with Riku instead.
- Riku has noted that Kairi and Naminé smell the same.