Black Singing Rival!

Black Singing Rival! is the 3 chapter of The World God Only Knows series' spin off, Magical Star Kanon 100%.

Synopsis
During a trip to Maijima pool, Kanon Nakagawa (also known as Maron in her child form) was playing with Kozue. It has been a month since she turned to a child and Elsie is currently posing as the actual Kanon and Maron wonders when will she turn back to normal. Kozue and Maron then say how wonderful this day is but suddenly, the sky is dark and the sun is pitch black.

The users of the swimming pool wondered what happened and suddenly, the temperature dropped to Winter levels and the public was suffering. Then, a girl and her pet owl approached and laughed at the spectacle. The girl, Bell Mark Atsume, a former idol who was turned to a child by a runaway spirit as well but decided to partner with her spirit to conquer the world.

Bell then said that she has used her powers to block all of the light in the city and no light will touch Maijima again. Bell's pet owl then said that it's master actually intended to block the whole world but was unable to do so because of her own limits and an irritated Bell orders her pet to keep quiet.

Maron then told Bell to stop this as Bell tells Maron (addressing her as Kanon)to come and stop her. At the same time, Okada called Kanon and said that because the Sun is blocked, the "hype" of sun and brightness themed building have lost meaning as Maron angrily said that this is not important.

Maron then saw Kozue fell over due to the extreme cold and transformed immediately to Magical Kanon to stop this. Kanon then demanded Bell to turn the city back to normal as Bell said that she too, is able to transform due to the power of song and challenged Kanon to a song battle.

Kanon then sang Natsuiro Surprise while Bell countered with Bloody Festa. However, Kanon cannot hear her own voice as Bell said that her music is different and begins to sing again. This time, Bell's song attacked through to Kanon and damaged her as Bell laughs at Kanon's weak powers.

Kanon then steels her resolve and did an encore and began to sing Summer Boy while Bell responded with Shadow Girl. With each song, Kanon kept falling however, by the 63 song, Kanon is still standing as Bell cannot believe her eyes. Bell's owl then said that she's nearly depleted her energy and soon, Bell reverted back to her child form.

Kanon then sang All 4 U as the grand finale and defeated Bell. As Bell asked how is this possible, Kanon replied that while Bell selfishly sang for herself, Kanon is singing for everybody (also her vocal training) and Bell was beaten off along with her spell that binds Maijima.

Later, when Kozue woke up she and Maron had some ice cream while Bell is singing in a karaoke club to train against Kanon.