The Testament of Sister New Devil_
Original: 新妹魔王の契約者
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!
Network
Tokyo MX
Episodes
22
Updated Feb 16, 2026
WHERE TO WATCH
Crunchyroll
19 countries
A
Aniverse Amazon Channel
1 country
Animation Digital Network
1 country
Watcha
1 country
TVING
1 country
Anime Times Amazon Channel
1 country
DROPTHE_ GOSSIP
Overview
The Testament of Sister New Devil has 2 seasons with 22 episodes spanning 2015.
Cast
Yuichi Nakamura →
Yuichi Nakamura stars as Basara Tojo (voice) in The Testament of Sister New Devil.
Yuichi Nakamura →
Rating
With a 7.9/10 rating from 341 votes, The Testament of Sister New Devil is considered highly rated.
Year context
The Testament of Sister New Devil first aired 11 years ago in 2015.
CAST (9)
Yuichi Nakamura
Basara Tojo (voice)
Ayaka Asai
Mio Naruse (voice)
Kaori Fukuhara
Maria Naruse (voice)
Tomokazu Sugita
Yahiro Takigawa (voice)
Yuu Asakawa
Chisato Hasegawa (voice)
Iori Nomizu
Kurumi Nonaka (voice)
Sarah Emi Bridcutt
Yuki Nonaka (voice)
Keiji Fujiwara
Jin Tojo (voice)
Seiko Yoshida
Zest (voice)
SEASONS (2 seasons, 22 episodes)
SEASON 1
01
The Day I Got A Little Sister
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…
02
First Contract Between Servant And Master
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…
03
Reunion and a Gap in Trust
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,…
04
Until Sadness Reaches Zero
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…
05
A Little Sister's Morning Demon Lording
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…
06
Bearing Growing Emotions
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…
07
The Depths of Love and Hatred
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…
08
Erotic Succubus Out of Control
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…
09
Merits and Demerits of Master and Servant
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…
10
Plaintive Betrayal
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…
11
Epsionage... What Lies After
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…
12
For This Night, This Moment
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.…
SEASON 2Burst
01
What I Can Do For You
After ending the battle against Zolgia, Basara regains his peaceful life with his two little sisters, Mio, the daughter of the previous demon lord, and…
02
Suspicions Deepening Within Mysteries
The day of the sports festival is finally here. Though Basara remains cautious of the mysterious enemy who manipulates people with magic, he happily enjoys…
03
My Cherished Feelings, For You
After taking Kurumi hostage, Ornis robs Basara of the right arm wielding Bynhildr. Though he lost conciousness from the pain, his sealed power unleashes and…
04
Amidst Entwining Plots
As the clash between the peaceful faction and the present demon lord faction draws near, Basara visits the peaceful faction along with Mio. Though Basara…
05
Amidst the Wind Blowing Through the Battlefield
Ramsus is out to extract the "Demon Lord's Power" that Mio possesses, and Basara reveals his anger at Ramsus' lack of concern for Mio's safety.…
06
Between Reality and One's Own Truth
Basara and the others recieve a message from Lars, calling them to Leohart's royal castle. Then Basara's father, Toujou Jin, appears before them all. He…
07
Between Entwining Plots and Desires
Basara and the others finally face the current demon lord, Leohart. Leohart's confidence in his strength fills the air as he welcomes them in without…
08
Those Contending For The Future
The group battle between Leohart and Ramsus's forces finally begins. After Mio wins the first match, Maria enters the arena for the next round. Her…
09
Beyond the Endless Dream
The only remaining match of the tournament is the duel between leaders, Basara vs Leohart. Basara finally appears after his long time in hiding, and…
10
The Consequences of What Must Be Done
The council's rampage sends quakes through the demon realm, and the demon Chaos is called forth through a giant magic circle. That commander of all…
SERIES INFO
2
Seasons
22
Episodes
24 min/ep
Per Episode
Ended
Status
NETWORKS (1)
Tokyo MX
DETAILS
FREQUENTLY ASKED QUESTIONS
What is The Testament of Sister New Devil about?
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 can I watch The Testament of Sister New Devil?
The Testament of Sister New Devil is available on Crunchyroll, Aniverse Amazon Channel, Animation Digital Network, Watcha, TVING. Availability varies by region.
How many seasons does The Testament of Sister New Devil have?
The Testament of Sister New Devil has 2 seasons with 22 episodes total.
Who stars in The Testament of Sister New Devil?
The cast of The Testament of Sister New Devil includes Yuichi Nakamura, Ayaka Asai, Kaori Fukuhara, Tomokazu Sugita, Yuu Asakawa.
What is the rating of The Testament of Sister New Devil?
The Testament of Sister New Devil has a rating of 7.9 out of 10 based on 341 votes on TMDB.
Is The Testament of Sister New Devil still running?
The Testament of Sister New Devil has ended. The final episode aired on .
GENRES (4)
Animation
Action & Adventure
Comedy
Sci-Fi & Fantasy
