
Quick answer — "GIRI GIRI" by Masayuki Suzuki featuring Suu from Silent Siren is the opening theme of Kaguya-sama: Love is War -Ultra Romantic-.
"GIRI GIRI" by Masayuki Suzuki featuring Suu from Silent Siren is the opening theme of Kaguya-sama: Love is War -Ultra Romantic-.
"GIRI GIRI" is performed by Masayuki Suzuki featuring Suu from Silent Siren.