りゅうぐうのつかいなら
竜宮の使いなら
ryūgūno tsukainara

Noun
Da Copula

The "-nara" conditional form ("if/when…") of りゅうぐうのつかい

1. If/when a messenger of Ryugu Palace…; As a messenger of Ryugu Palace…

Nara Conditional
Usually Written in Kana