Toujou Basara is a high school student whose father has suddenly just remarried. His father then departs overseas leaving Basara with two new beautiful step-sisters. Little does he know, his new sisters, Mio and Maria are actually the new Demon Lord and a succubus!? Almost trapped into a life of servitude, Basara forms a reverse contract by accident and ends up becoming Mio's master! Hijinks ensue as Basara finds himself in one ecchi situation after another. However, Mio's life is in danger as she is pursued by demons and heroes!
The Testament of Sister New Devil (Season 1)
The Day I Got A Little Sister (Episode 1) 7.6
Air date: 2015-01-07
Runtime: 25 min
Overview: Thanks to his father's sudden remarriage, Toujou Basara finds himself with two beautiful new step-sisters. Their names are Naruse Mio and Maria. Mio wakes him up in the morning, while Maria stands in the kitchen wearing a suggestive outfit...
First Contract Between Servant And Master (Episode 2) 7.5
Air date: 2015-01-14
Runtime: 26 min
Overview: As daughter of the former demon lord, Mio's foster parents were slain by powerful demons after her life. Still seeking to slay her, Basara reveals himself as a member of the hero clan--an enemy of the demons--and vows to protect Mio as a member of his family.
Reunion and a Gap in Trust (Episode 3) 6.3
Air date: 2015-01-21
Runtime: 25 min
Overview: Basara's childhood friend Nonaka Yuuki warns him not to get involved with Naruse Mio any longer. She is a fellow member of the hero clan, and the one charged with observing Mio. She claims that Mio will bring great disaster, but Basara proclaims that he will protect Mio as a girl on his own.
Until Sadness Reaches Zero (Episode 4) 6.0
Air date: 2015-01-28
Runtime: 25 min
Overview: Basara suffers a deep wound in the battle against the white-masked man after Mio's power. Mio regrets getting Basara involved, and challenges the white-masked man to battle on her own. Meanwhile, in order to protect Mio, Basara resolves to use the "forbbiden art" he sealed away after the events of his past. What was the tragedy that visited the hero village and Basara?
A Little Sister's Morning Demon Lording (Episode 5) 5.2
Air date: 2015-02-04
Runtime: 25 min
Overview: With the battle against the white-masked man settled, they returned to their bawdy daily life. Basara wakes up with his hand groping Maria's butt, he runs into a naked Mio when he enters the bathroom, and Yuki sneaks into the bath with him. The master-servant pact lying at the heart of everything. Accoring to Takigawa, his classmate and the white-masked man, the pact between Basara and Mio holds another secret. Meanwhile, Basara's childhood friend Yuki invites him out on a date...
Bearing Growing Emotions (Episode 6) 5.3
Air date: 2015-02-11
Runtime: 25 min
Overview: Basara goes on a date with Yuki. Unaccustomed to the shopping center, when the two of them are overwhelmed by a clerk's sales talk, Mio stops following to rescue them.
The Depths of Love and Hatred (Episode 7) 5.5
Air date: 2015-02-18
Runtime: 23 min
Overview: Basara leads Mio to higher peaks as he pursues pleasure with the use of syrup. With their master-servant pact reaching a new level, they both bring their full might to face the ones trying to eliminate Mio: Takashi and Kurumi.
Erotic Succubus Out of Control (Episode 8) 7.8
Air date: 2015-02-25
Runtime: 24 min
Overview: Ten days pass since the battle with Takashi and others. Although the battle ended with reconciliation, Yuki returned to the hero's village. ...or she was supposed to, but when Basara returns home, he finds Yuki in an apron!
Merits and Demerits of Master and Servant (Episode 9) 8.3
Air date: 2015-03-04
Runtime: 24 min
Overview: Basara and Yuki begin the ceremony to form their pact. Clad in a bustier and garter belt, Yuki was raring to go for it, but she refused to forge the pact normally, and suffered the same succubus curse as Mio.
Plaintive Betrayal (Episode 10) 8.0
Air date: 2015-03-11
Runtime: 24 min
Overview: Mio has been captured by Zolgia following Maria's betrayal. Basara too is captured by Lars and brought to Zolgia's mansion. Lars' goal is to exchange Basara for Mio. He explains that he's only doing his duty as Mio's observer, but negotiations fail, and Zest slays him.
Epsionage... What Lies After (Episode 11) 5.2
Air date: 2015-03-18
Runtime: 23 min
Overview: Strength as a human, the power to rend evil--With the power inherited from his father, Tojou Jin, Basara faces off against Zolgia. Basara is driven by the desire to protect his precious family. That desire gives him strength, and even as Zolgia pushes him to the edge, he rises without breaking. However, even Basara eventually runs out of strength facting that all too powerful might. His mind in despair, he's unable to escape from Zolgia's dominion...
For This Night, This Moment (Episode 12) 7.3
Air date: 2015-03-25
Runtime: 25 min
Overview: Everyone is trapped inside the body of the demon realm's most dangerous creature, a beast capable of infinitely multiplying until it swallows the entire world. Dimensionally cut off, the only remaining option for Basara and the others is to completely eliminate this dangerous creature's vital core.
