Koneko-chan doesn't have any involvement in Raku's romance, or even any other defining characteristics. At times it seems like she is aware of her true nature, horrified at the world and show in which she lives. Other times, it seems like she is high or intoxicated, supposedly to run away from the Awful Truth.
Or, Raku could be mentally disabled, Koneko is friends with her out of sympathy (or legitimate friendship) and Hitoshi is being a dick and teasing her.
Fridge Brilliance: After Raku-chan's death, Bokutachi-San is seen acting cheerfull and happy, even taunting Hitoshi-San for killing her by breaking her heart. It seems pretty cruel until you remember Koneko and Raku previously foiled his attempts to molest Hitoshi. Of course he'd be happy to see one of them gone.
Shocking Swerve: The show starts as a (really bad) Slice of LifeFanime, but over the course of the story, terrible things happen to Raku-chan, and they actually stick! This all culminates in the Grand Finale, where she outright DIES.
Raku-chan's death's aftermath. Oh sure, her death in itself is hilariously narmy, but the reactions of the other characters, and especially the end theme are depressing as all hell.
Hell, Raku-chan's death was pretty tear jerking thanks to a combo of Animation Bump and Raku-chan's voice-acting during her final sayonara to Hitoshi and Koneko being done a LOT better in this scene.
From the word go, episode ten was a tearjerker. After only nine episodes, the fanime that has grown on you has come to a close. This is it, the last episode, the grand finale... Then the video starts and you find that the sugary and hopeful opening theme True Love has been replaced with the heart-rending love ballad Is This Love by Whitesnake...