There are at least 3 artists with this name:

1) Eiko Shimamiya (島宮えい子) is a singer in the Japanese group I've Sound.
2) The alias of Swiss singer Joana Aderi. She has released the album "I feel pregnant today" in 2007.
3) EIKO (voiced by: Kaede Hondo, singing voice: 96neko, live-action drama actress: Moka Kamishiraishi (上白石萌歌), also known as adieu) is the primary character of the anime series Ya Boy Kongming! (2022) and it's live-action drama adaptation with the same name (2023). Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.