My Friend's Little Sister Has It In for Me! Volume 6

With the summer festival behind them, it’s time for Akiteru to get back to finding Iroha a friend! But nothing ever goes according to plan. What’s he to do when his friend’s little sister doesn’t seem to have it in for him anymore? How can he find her a friend she can be annoying with when she doesn’t want to be annoying anymore? When Akiteru tries to talk some sense into her, she instead talks him into competing at the school’s culture festival for the title of...Queen Nevermore?! It’s now up to Akiteru to defy the odds and become the prettiest girl at school! But will that really help Iroha get back to her usual (annoyingly cute) self...?

[From J-Novel Club]