Ratrium

 is a "Black&Piano-Pop" music unit formed in 2016 as an a capella unit under the name Groovy groove. They changed their name to Ratrium and started activities as a pop unit in March 2020.

Members

 * Shige - Arrangement
 * mori - Vocals/Composition

Cover EPs

 * [2018.08.08] Groovy Covers Vol. I
 * [2019.02.12] Groovy Covers Vol. II
 * [2019.08.12] Groovy Covers Vol. III
 * [2020.01.09] Groovy Covers Vol. IV

Digital Singles

 * [2020.03.04] Koko Dake no Hanashi (ココダケノハナシ)
 * [2020.03.21] Koko Dake no Hanashi (A Cappella Ver.) (ココダケノハナシ (A Cappella Ver.))
 * [2020.04.15] Jinsei Itsumo Sanyuukan (人生いつも三遊間)
 * [2020.05.20] clover
 * [2020.06.24] Shuushifu Sengen (終止符宣言)
 * [2020.07.29] Halcion Days
 * [2020.08.26] Kawaii Never Die
 * [2020.09.30] Biscuit Strategy (ビスケット・ストラテジー)
 * [2020.10.28] Popping Shower Love
 * [2021.03.17] Seishun Pierrot (青春ピエロ)
 * [2021.05.19] Sweat (スウェット)
 * [2021.08.11] Petrichor wo Eien ni (ペトリコールを永遠に)
 * [2022.03.30] Shunjin (春塵)
 * [2022.06.15] Uso no Aji (嘘の味)
 * [2022.07.27] Lemon Cider