4U pronounced as "For You" is the first rival unit in the series and consists of Ume Kujou, Emoko Wanibuchi and Hina Saeki.
- Ume Kujou - The lead vocalist, guitarist and founder of 4U.
- Emoko Wanibuchi - The bassist of 4U.
- Hina Saeki - The drummer of 4U.
- ワタシ・愛・forU!! (Watashi Ai forU!!) - The debut song for 4U.
- Hello...my friend
- TREAT OR TREAT?
- Hello...my friend (Emoko Version)
- Hello...my friend (Hina Version)
- TREAT OR TREAT? (Emoko Version)
- TREAT OR TREAT? (Hina Version)
- This is the only rival unit to feature three members.