Melascula

is an elite warrior of the Demon Clan, serving directly under the Demon King as the Faith of the Ten Commandments.

Appearance
Merascylla is a dainty woman with long, pink hair. She wears a sleeveless leotard with a pink bow on the choker. She also wears long, pink stockings. She is constantly cloaked in shroud of her own darkness. Though not readily apparent, she also has an abnormally long tongue accompanied by the enlargement of her mouth.

Personality
Merascylla has a calm, yet mocking personality. Upon being released from the seal she wishes to rest before acting and when the Ten Commandments realize that they may reclaim their lost magical power by consuming the souls of humans, she chooses to summon some lesser demons instead of having to work themselves. She also seems to look down on humans, in general.

3,000 years ago
Along with the rest of the Demon Clan, Merascylla was sealed away by the Goddess Clan after losing the Ancient War against the Four Races (Human, Fairy, Giant, and Goddess Clans).

Albion arc
After Hendrickson manages to remove the seal, Merascylla and the rest of the Ten Commandments appear before the terrified former Great Holy Knight and Fraudrin in Dreyfus' body. After being informed by Fraudrin of the current events in Britannia, Zeldris suggests that they should head for Edinburgh Hill for recuperation of their severely drained magical powers, on which everyone agrees. They fly out of Zhuhur Valley, leaving a terrified Hendrickson.

Arriving at Edinburgh Castle, Derrierie and her fellow Ten Commandments find it in ruins and conclude that a powerful magical implosion caused the destruction of the castle; they also find a large hole, which they link to Meliodas. The Commandments discuss the destruction of the Albions and Galan decides to attack Camelot. Later on, the Commandments begin to recover their magical power by consuming the souls of humans, and Merascylla summons a Red Demon and Gray Demon to collect souls for them. These two are stopped by the Three Misfits and Hendrickson.

Istar arc
She is shocked when she senses Meliodas regain his full power at Istar. When Meliodas appears, thanks to Merlin's teleportation magic, she along with the other Commandments, except Galan, are surprised to see him. She watches as Melodias defeats Galan in five seconds and he warns Zeldris that the Seven Deadly Sins would defeat the Ten Commandments with everything they've got. In response, Zeldris and Fraudrin attack Meliodas from both sides, but he is teleported back to Istar. Galan is angered and humiliated by his defeat at the hands of the "Accursed Demon."

Merascylla appears next to Galan, who is contemplating his revenge, and states that he could not beat Meliodas as he was. Afterword, Zeldris orders them to split up and move across the land to regain their magic faster. Upon hearing this order, Merascylla splits off with Galan. It is later shown that she is calling back the souls of the dead to use as her own army of Zombies to wipe out the living humans. Upon sensing that one of the souls she revived was resisting her magic, she and Galan decide to check it out and encounter Ban of the Seven Deadly Sins, who states he will kill them.

Angered, Ban picks out his Three-section Staff, but Galan cuts his torso before he could attack. After knowing of the commandment's defeat by Meliodas, Ban comments on their mentioning of Meliodas' relation to the Demon Clan. A furious Galan asks how he's still alive and Ban announces himself as Merascylla began to attack on her turn, but Ban avoided her attacks easily. Galan crushes the bandit's head but he recovers from that as well much to their shock. Galan then offers Ban to hit him once in honor of his feats, and Ban prepares his Hunter Fest, robbing Galan of his power and delivering a massive kick to the commandment's gut. Ban continues with his assault on Galan and soon shifts to attempt a hit on Merascylla, but she survived using her power. Galan attempts to attack Ban again but fails to land a hit, while Ban counters with his fists. Merascylla deduces to Ban's Snatch abilities and warns Galan, Ban continuing to provoke them at the other hand.

Although Ban almost wins the battle after he uses Hunter Fest on Merascylla and Galan, he finally exhausted. Jericho later carrying Ban and Elaine and flees from Merascylla and Galan who give deadly pursuits to them. The two Commandments discovered a bar called "My Sweet Gluttony" inside a dark cave where Ban, Jericho, and Elaine were hiding.

The owner of the bar, Escanor became terrified when Galan gets distracted by the booze and immediately commences drinking along Merascylla. Admiring how the booze has gotten better over the course of 3000 years, Escanor explains its content which Merascylla credits him for knowing much about it. Escanor asks who they are and the due respond that they're the Ten Commandments of the Demon King. Surprised, Escanor is challenged to a Galan game, with each of them delivering a blow to the other and the first one to die loses. Despite Jericho and Ban's advice, a terrified Escanor accepts the game and is patted in the back by Galan, but the force Galan used caused the secretive sin to pass out. Before they noticed it, morning had already arose, and as Galan attempted to carry the Rhitta, Escanor snatched it from his hand and told him that mere demons cannot hope to wield this axe. A surprised Galan wonders whether he is human or not and Escanor responds that he is indeed human, but he is the very pinnacle of the human species, introducing himself as the The Lion's Sin of Pride, Escanor of the Seven Deadly Sins.

After defeating Galan, a shocked Merascylla commends on Escanor's great power, so great Galan broke his own oath and subliminally tried to escape, but was petrified due to breaking his oath while Escanor proceeds to sigh in disappointment. Escanor tells her that if she wants to run away he'd allow her as he still has some chivalry in him, but a she decides to use her Cocoon of Darkness to try and rob Escanor off his soul. Inside the cocoon she states she is tired of listening to all of Escanor's arrogant talk and asks he be quit forever, as she removes and devours his soul. However, she is soon struck with intense pain, feeling as if her entire body is on fire.

Escanor's soul flies from her mouth and as she is consumed in flames she screams how could his soul contain so much power and what kind of power it is. As Escanor tells her the name of his ability, his soul having returned, she screams in agony as she is consumed in flames, falls over a cliff, and seemingly splits in half. Whether she survived or not is currently unknown.

Abilities and Equipment
Like all members of the Demon Clan, Merascylla is able to utilize the mysterious jet-black matter as shown forming wings for flight.

As a member of the Ten Commandments, she is exceptionally powerful. Her aura, combined with the other Commandments', is so powerful that it made the normally calm Hendrickson sweat in fear by their mere presence.

Commandment
Merascylla was bestowed the commandment of by the Demon King, meaning that any who show faithlessness in her presence will have their eyes set ablaze.

Abilities

 * Merascylla is able to use her cloak of darkness to form a portal to summon lesser demons to do her bidding.
 * A forbidden spell that amplifies the lingering affection and regrets of the dead. It gives life to rage that would otherwise have no outlet and calls them back to the world of the living. If the dead resists their rage and their grudge disappears, death awaits them once more.
 * Merascylla envelops her opponent in darkness, trapping them within a pitch black sphere.

Zeldris
She is often near him and seems to respect him a great deal. When Galan wants to slack off and drink she berates him, stating that Zeldris would be furious.

Galan
Though they have their disagreements the time we see of them alone shows that they are actually good friends who enjoy each others company and drinking together. She says she teamed up with him in order to look after him and after Galan is turned to stone by his own curse against Escanor, she is noticeably distraught.

Ravens arc

 * Ban vs. Galan & Merascylla: Indecisive
 * Escanor vs. Galan & Merascylla: Lose

Trivia

 * Merascylla's commandment, "Faith", ability may be based on the first/second commandment of the Ten Commandments: "Thou shalt have no other gods before me." The commandment dictates unwavering faith towards the one true god with threat of severe punishment.
 * In Greek mythology, Scylla was a monster that lived on one side of a narrow channel of water, opposite her counterpart Charybdis. Sailors navigating the strait could choose to avoid one, but not the other. She most famously appears in Homer's Odyssey, where she consumes six of Odysseus' crew alive after they are distracted by Charybdis.