The Testament of Sister New Devil

Season 1

TV-MA

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!

Where to Watch The Testament of Sister New Devil • Season 1

12 Episodes

The Day I Got A Little Sister
E1
The Day I Got A Little SisterAfter Toujou Basara's father remarries, Toujou gains two step-sisters named Maria and Mio.
First Contract Between Servant And Master
E2
First Contract Between Servant And MasterAs 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
E3
Reunion and a Gap in TrustBasara'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
E4
Until Sadness Reaches ZeroBasara 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
E5
A Little Sister's Morning Demon LordingBasara's morning starts with Maria in his bed, followed by Mio and Yuki in the bathroom. The hero clan upgrades Mio's status to kill.
Bearing Growing Emotions
E6
Bearing Growing EmotionsBasara 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
E7
The Depths of Love and HatredBasara 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
E8
Erotic Succubus Out of ControlTen 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
E9
Merits and Demerits of Master and ServantBasara 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
E10
Plaintive BetrayalMio 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
E11
Epsionage... What Lies AfterBasara and then his sisters take on Zolgia, when he is injured the true form of the building they are in reveals itself to be a creature, resulting in them being trapped inside it's belly.
For This Night, This Moment
E12
For This Night, This MomentEveryone 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.