This post is referencing Kei's overwhelming popularity at Comiket 108, she had over 130 doujinshi at the event, making her the first Blue Archive character to surpass 100 doujins. Her individual doujin count was more than double the next most popular student, and even surpassed individual series like Azur Lane. Some have made jokes of her being the Second Queen of Ariake, which is referencing Kancolle's Kashima, who was initially referred to as the Queen of Ariake due to her popularity at Comiket in 2015. Ariake is the location at which Comiket is held.

Doujin Counts by Student

Sourced from reddit

You can see Series counts here - Azur lane reportedly had 112 circles, whereas the above mentions Kei had 135.