Complex sentence: Suzuka became a member of the, which released songs under the name Babymetal, which also included fellow Sakura Gakuin members Yui Mizuno and Moa Kikuchi.
Split into simpler sentences: Suzuka became a member of the, which released songs under the name Babymetal. That group also includes fellow Sakura Gakuin members Yui Mizuno and Moa Kikuchi.