Sealing Technique, Release!

Sealing Technique, Release! is chapter 28 of the Boku wa Tomodachi ga Sukunai light novel series. It is chapter five of volume three.

Summary
In the midst of the heat wave, the air conditioning unit in Kodaka's house malfunctioned. Arriving with the groceries, Kodaka informed Kobato on the three-day wait before their new air conditioning unit would be installed in their living room. Kodaka then advised Kobato to wear lighter clothing, which Kobato rejected, as she claimed that her Gothic clothes are seemingly attached to her as a material form for her dark powers.

After watching her favorite anime, Kurogane no Necromancer, Kobato decided to change into her "true form" by changing into some lighter clothes in front of her brother which she once wore in her elementary days. After mentioning this to Kobato, Kobato wailed and then reassured herself (in Leysis mode) of not aging due to her being a vampire as she mispronounced the word "decrepit" as "deprecit", much to Kodaka's dismay.