以津真天 - Itsumade

太平記より、毎夜、紫宸殿上空で「いつまでいつまで」と鳴いて天皇を苦しめ真弓広有に射落とされた怪鳥。

From the Taiheiki, a monster bird was shot down by Hiroari Mayumi, who tormented the Emperor every night by singing "How long, how long?" in the sky above Shishinden.