Keiji Kyoukai no Mologue

Keiji Kyoukai no Monologue is a song sung by the unit fulfill. The MV was released on March 30 2019.
 * "形而上(Keiji Jou)" means metaphysical.
 * "形而下(Keiji Ka)" means physical /material.
 * "境界(Kyoukai)" means Boundary.