Sariel is an angel from Ente Isla with the duty of carrying out the declaration of the Fallen, ensuring that those who go against the Church and divine order are eradicated or punished. He is sent to Earth with the mission of recovering the sacred sword Better Half, believing that Emilia having distanced herself from the Church no longer has the right to wield it.

To accomplish this, he first attacks Emilia at a convenience store, disguising himself as a masked robber in an attempt to catch her off guard. Failing this, he takes on the alias “Mitsuki Sarue” and establishes himself as the manager of Sentucky Fried Chicken, a competitor to MgRonald’s, where Maou works. His goal is to observe and gather intelligence on both Maou and Emilia in their human lives before striking.

Eventually, he teams up with Crestia Bell (Suzuno Kamazuki), convincing her to help eliminate Maou and Emilia under the belief that justice must be served. However, despite his ruthlessness in battle, his erratic and flamboyant behavior makes him a source of unintended comedy, as he often overreacts, gloats excessively, and acts arrogantly despite repeated setbacks.

Sariel has a delicate, almost feminine appearance, with silver-white hair, pale skin, and sharp violet eyes. His angelic features give him a serene yet unsettling presence, as his smiling face often hides his more sinister nature.

In his human disguise as Mitsuki Sarue, he wears a white Sentucky Fried Chicken uniform, presenting himself as an eccentric and overly enthusiastic fast-food manager. However, his angelic aura remains noticeable, making him stand out despite his attempts to blend in.

When he fights seriously, he manifests a large pair of angelic wings, and his scythe glows with divine energy, reinforcing his status as an executioner of divine will.

Sariel is a contradictory mix of ruthless and ridiculous. As an angel, he is cold, calculating, and highly arrogant, believing himself to be above humans, demons, and even other angels. He speaks in a condescending and authoritative manner, dismissing those he sees as beneath him.

However, he also exhibits a childish, eccentric, and comedic side, often overreacting in dramatic and exaggerated ways when things do not go as planned. He has a twisted sense of justice, insisting that Emilia return Better Half to the Church, despite the fact that she is the rightful wielder of the weapon.

One of his most bizarre traits is his obsession with beautiful women, particularly Emilia and Chiho. He develops an unhealthy infatuation with Chiho, frequently making creepy and inappropriate remarks about her, which earns him beatings from Emilia whenever he crosses the line.

Despite his comedic shortcomings, Sariel remains a dangerous opponent, as his ability to nullify sacred powers makes him a serious threat to Emilia and other divine warriors.

• First Attack on Emilia
  Sariel first attacks Emilia at a convenience store, disguising himself as a masked robber in an attempt to catch her off guard. However, his plan fails, and he is forced to retreat, leading him to adopt a more calculated approach.

• Infiltrating Earth as Mitsuki Sarue
  To observe Maou and Emilia, Sariel takes on the identity of Mitsuki Sarue, posing as the Sentucky Fried Chicken manager in Hatagaya. He frequently spies on MgRonald’s, trying to learn more about Maou’s human behavior while gathering information about Emilia’s sacred sword. His fast-food rivalry with Maou leads to unintentionally hilarious moments, as he treats their business competition as a serious conflict, failing to realize how absurd it is in comparison to their battles in Ente Isla.

• Teaming Up with Suzuno
  Sariel manipulates Suzuno Kamazuki (Crestia Bell) into joining forces against Maou and Emilia, exploiting her loyalty to the Church to convince her that eliminating Maou is the right path. However, as Suzuno begins to question her allegiance, Sariel’s plan begins to unravel.

• Battle Against Emilia & Defeat
  Sariel eventually engages in direct combat with Emilia, wielding his scythe and using the Wicked Light of the Fallen to suppress her sacred power. He demands that she return Better Half to the Church, arguing that she no longer has the right to wield it. Despite his initial advantage, Sariel is ultimately defeated, humiliated, and left powerless in Japan, much like many of the other supernatural figures trapped in the human world.