Big sister's best friend with shotacon tendencies...hell, Yamamoto's little brother is one step away from knocking out the some 18+ rated genre bingo. But all jokes aside, I like that despite being a gyaru, Yamamoto is still the type of person who is forced to be a straight man among the weirdos around her. First a spoiled and arrogant brother, then a best friend with an excessive sense of ownership. Thanks for the chapter, I heard that the manga was on hiatus so I'm glad to see some updates.
P.S. I think that if Wada was a adult woman, she could very well become obsessed with some host and throw him tantrums like this for real, lmao.