Major spoiler warnings: It's honestly super annoying that yandere mangaka insist on making sure the yandere character is murdered or commits suicide by the end. Usually it's at least done in a way that makes sense given the context of the rest of the story. This story does not. The ending makes absolutely no sense given Sazi-chan's character, who is before shown to be getting better, making friends, etc, and then she abruptly decides to kill herself. The ending is not perse unimaginable. It's just a slap in the face of a manga which was clearly headed to a happy ending otherwise. The main thingthis manga has going for it is Mero's personality, Mero and Sazi's personality, the gorgeous art, and Sazi's personality, in that order. It makes for a fun, slihgtly bloody romcom, because Sazi's portrayed as violent but ultimately harmless, which is why Mero finds her amusing. That makes it especially strange that Sazi compares herself to Usagi. At one point, Sazi chases Mero around with a knife, but it's clearly meant to be played for laughs because Sazi has many, many opportunities to murder Sazi. Sazi being violent is always played for laughs, but once Usagi does her thing, the author tries to pretend like that was serious. Even when Sazi straight up kidnap's Hikari, she almost immediately unties HIkari.

Everything after volume 1 just went to shit. Even up until the last chapter, it would've made perfect sense to have a third volume where HIkari and Sazi properly bonded. Honestly, Hikari's personaliy is sort of bland and she's not actually interesting as a character whatsoever. But that was the perfect opportunity to do that, because the major conflict had been resolved, and the three girls were able to bond and become friends. But then the author said "haha what if sazi killed herself though lol" and ended the manga there. Given Mero and Sazi's growing bond, and Mero's attachment to Sazi, and her implying at one point that she found Sazi rather pretty, it would have just made perfect sense for Mero and Sazi to fall in love. Mero is portrayed to be closer to Sazi than Hikari and showers her with attention, and accepts her as the broken girl she is, and Mero is canonically cute, and they have chemistry.

Overall in spite of the stellar first volume, and the hilarious relationship between Mero and Sazi, Usagi's introduction had major negative efffects on the nature of the story due to her aggressive personality, drastically bringing down the quality of the series.