The Seven Deadly Sins (七つの大罪 Nanatsu no Daizai) series is a series of songs made by mothy, also known as Akuno-P. The series is currently slated to have at least eight major components, and the songs were put into the album 悪ノ王国 ~Evils Kingdom~ which was released on December 22, 2010.

The series focuses on the "cardinal Sins", the vices used since ancient Christian times in order to instruct on the morality of humanity. While more minor sins, "venial sins", could be easily forgiven through sacraments, the cardinal sins would lead one to eternal damnation if not absolved through Penance or perfect contrition.
The theme is common in Catholic tradition. The definitions have changed throughout the years, but there is a general agreement on the current seven with their current Latin names.
The series focus in 7 songs, 7 moments in The Evillious Chronicles when the Seven Deadly Sins reached their climax, causing masive suffering and death.

Superbia (Pride)
Daughter of Evil

Sung by Rin Kagamine

The song "Daughter of Evil" was uploaded on April 6, 2008. This one spawned its own subseries of sung by Rin Kagamine, Len Kagamine, Haku Yowane and Hatsune Miku, known as the Story of Evil.
The songs concern Lucifenia, a kingdom ruled by Rillianne Lucifen d'Autriche (Kagamine Rin), a princess who, on top of being tyrannical, became jealous when Kyle Marlon (Kaito), the prince she fell in love with was in love with another girl, Michaela (Miku). Fueled by this, she orders the destruction of the girl's kingdom and the women in it. Her servant, Allen Abbadonia (Kagamine Len), who is actually her twin brother, is so loyal to his sister that he will kill in order to keep her alive. She ruins the lives of many in order to keep her own goals alive - and is forced to become repentant when her brother finally sacrifices himself for her. Akuno-P gave keywords to this song,「オーホッホッホッホ。さあ、ひざまずきなさい!」 ("Oh ho ho ho! Now, bow before me!" which is also its initial phrase. The official English title of the song is "The Princess of Lucifer".

Gula (Gluttony)
Repulsive Food Eater Conchita

Sung by Meiko
backup by Rin Kagamine and Len Kagamine

The song was uploaded on March 3, 2009. The song concerns Vanika Conchita (Meiko), a woman who, at one time, ate only the most delicious and exquisite food. Now, however, her tastes have evolved so that she wants something new and grotesque every day, and nothing enters or leaves her palace. The fifteenth personal chef of the year asks for a brief vacation, but she, angry, decides to eat him. Running out of food to eat, she ends up eating her butler and maid, and when everything has gone, she ends up eating herself - which nobody else will ever know what it tastes like. Akuno-P gave keywords to this song,「敬い称えよ われらが偉大なコンチータ」(“Bow down and worship our great Conchita”) and its initial phrase is 「さあ、残さず食べなさい」 (Saa, noko sazu tabenasai "Now, eat them out". The official English title of the song is "Beelzebub Party".

Invidia (Envy)
The Tailor Shop at Enbizaka

Sung by Luka Megurine

The song was uploaded on December 7, 2009. The song concerns Kayo Sudou (Luka Megurine), a tailor in the fictional city of Enbizaka (enbi = envy), who is known for her skill. The only thing she thinks about most of the time is the fact her "lover" is unfaithful and does not come "home". She sees him walking with a woman in a red kimono and murders her with her tailor scissors and takes the kimono, acting as if nothing had happened and that she is concerned about the rising murder rate. She later sees him with a girl in a green sash and does the same to the girl, taking the sash - the same happens with a girl with a yellow hairpin. The tailor dresses herself in the kimono, sash, and hairpin, thinking that she has made herself beautiful for him. But as it turns out, the man does not even know her; the three females were his wife and daughters, and so when he meets the tailor, he does not recognize her. Offended at this apparent lack of acknowledgment, the tailor murders him, too, and carries on with her work. Akuno-P gave keywords to this song,「だけど仕事は頑張らなきゃ」("But I must persevere with my work." and its initial phrase is 「さあ、仕立てを始めましょう」(Now, I shall tailor). The official English title of the song is "Leviathan Slope".

Luxuria (Lust)
The Madness of Duke Venomania

Sung by Gakupo Kamui
backup by Luka Megurine, Miku Hatsune,

The song was uploaded on July 25, 2010. The song is about a man, Duke Sateriajis Venomania (Gakupo), who, in his childhood, had been mocked and taunted by others. In adulthood, he made a deal with the devil to have an irresistible charisma to women. As a result, women are now flocking to his mansion's basement to create a harem for him. One of these women happens to be the one who "made him for a fool", his childhood friend, Gumina Glassred (Gumi). However, a jealous man, Kachees Crim (Kaito) who had lost his love to Venomania , came to his palace, disguised as a woman, and stabbed him in the chest with a poisoned knife. The charm now broken, the women flee from his mansion, and as Venomania dies, he sees a glimpse of his childhood friend, and reveals that he had truly loved her. Akuno-P gave keywords to this song, 「踊ろうよ このハーレムで」 (“Let's dance in this harem”) and its initial phrase is 「さあ、踊ろうか」 ("Now, Shall we dance?". The official English title of the song is s"Dance with Asmodeus".

Avaritia (Greed)
Judgment of Corruption

Sung by Kaito

The song is focused on Gallerian Marlon (Kaito) , a young clever judge who is willing to receive bribes to make criminals "innocent". The reasons are to get the money and the resources needed to help to his handicapped "daughter" (Miku) and to achieve his goal of collecting the Seven Deadly Sins, needed to realize his wish of restoring the condition of his "daughter". Later, he is bribed by a general who is about to be sentenced to death for mass murdering. Although it is a capital offence, the general is deemed innocent. As a result, a civil war starts which kills the general. This also leads the burning of the judge's mansion along with him and his "daughter". Killed in the fire, the judge wakes up in the Afterlife with no clue if he is in Hell or Heaven. The "master of the hellish yard" (Gumi) tells him that he can be saved if he gives up his money, but he tells the "master of the hellish yard" that he will never give his fortunes to her, or anyone. He is later sent to Hell, hoping that the place will turn into "utopia" for himself and his "daughter" after he gathers his sins. The song is directly related to "Girl of a Miniature Garden" and "Heartbeat Clocktower". Akuno-P gave keywords to this song, 「地獄の沙汰も金次第」("Money is the best lawyer in hell" and its initial phrase is 「さあ、開廷の時間だ」 ("Now, let the trial begin". The official English title of the song is "Mammon's Court".

Acedia (Sloth)
Gift from the Princess who Brought Sleep

Sung by Hatsune Miku

This song concerns Margarita Blankenheim (Miku Hatsune), shown as the daughter of a doctor, who is made to marry Marquis (Kaito), a man who is blinded by money. She learns form her friend Julia (Meiko) how to make a medicine which puts everybody to sleep. She then makes everyone drink her 'remedy', which in actual fact is just a poison. After putting everyone in the city to "sleep," in the end she commits suicide by drinking her own poison.
At the end of the PV, a dialogue between Elluka Clockworker and Gūmilia (both characters from mothy's Daughter of Evil novel) is shown, hinting the relationship of Margarita and Julia with Pere Noel. This song's keywords are 「あなたの幸せの為に」 "For the sake of your happiness", and its initial phrase is 「さあ 眠りなさい・・・」 ("Now, go to sleep". The official English title of the song is "Belphegor's Gift".

Ira (Wrath): Unknown Gumi song

Not released yet.
"Heartbeat Clocktower" revealed this song would be sung by Gumi; however, nothing else is known. "Caprishio Farce" though confirmed as "Clockwork Lullaby 6" is rumored to also be the Ira (Wrath) song as well. However the rumors are currently believed to be incorrect.