/jp/ - Otaku Culture

Tenshi is the eldest daughter in the Hinanawi clan, and Iku seems to be on a somewhat friendly level with her. In Scarlet Weather Rhapsody, Iku was supposed to report the earthquake, but none of the Hinanawi clan members were home. In Iku's ending, it's revealed that she's aware of how reckless an spoiled Tenshi is, and has never been happy about it.

Iku's win quote implies that Tenshi's father, Lord Nai, gets mad whenever Iku reported him, and that Iku often complains about it to Tenshi. Tenshi, however, sees Iku as just a messenger. Although Iku has always been unhappy with Tenshi's, it was Tenshi's act of using a keystone without permission that made Iku snap, leaving her post in the clouds to find Tenshi and punish her.

Because Iku doesn't have any authority over the Hinanawi clan, this means that all before Iku could only complain and not take action.