Rachnera is clever and streetwise, thinks that it is alright to break rules as long as nobody finds out and manipulates Ms. Smith (who, as her Coordinator, had been totally negligent about her and her situation) into assigning her to Kimihito's household much to the discomfort of Miia and Cerea, who are especially wary as Rachnera is a fearsome-looking predator. Rachnera enjoys annoying most of the household and hones her web-making skills by setting traps for everyone which typically result in them being unwillingly tied up in bondage positions.

https://youtu.be/BA4eEjuS_1E?t=38