The Light Novel series is the source material for the adaptation of the Anime and Manga series. The information and terminology on the article will be based on the source material rather than the adaptions.
Kai grew up in the orphanage and was part of a group of boys that spent most of their time together which also included Gil. Despite this he didn't have a high opinion of Gil, remarking at one point that Gil was probably chosen as the commoner blue shrine maiden's attendant, because he was the most useless grey robe in the temple.
On the way through the Lower City he and others reminesce about their hopes and first impressions of Myne and how much Gil changed in the short time since becoming her attendant. They also marvel at how much Myne had already helped them despite or maybe exactly because of being just a commoner.
He remarks that with Myne having so few attendents, it is likely that she will soon get more, which motivates many of the orphans to work extra hard and distinguish themselves for a chance to be chosen by her once this happens.