Melascula

Melascula or translated a few times as Merascylla, she is one of the member of Ten Commandments, and she serves the Demon King as the demon of faith.

History
3,000 years Melascula was a poisonous snake that bathed in Demon Realm miasma and thanks to that Melascula gained anthromorphic attributes, such as turning into a giant snake and can transform itself into human form at any time in his life, Melascula chosen as the Faith of the Ten Commandments by Demon King.

Holy War
Later when Ludociel imprisoned a horde of demons, the Ten Commandments, Monspeet, Derieri, Garland and Fraudrin lead a demon army against Fairy King's Forest, and the demons were soon confronted by Elizabeth who wanted the Demon Clan. While the demons were almost destroyed by the attack caused by Archangels Sariel and Tarmiel but the Ten Commandments survived. After that, Melascula was still taken to the Celestial Realm gate where she was betrayed by Gowther who freed the true Gowther grabs Melascula's head and immobilizes her with her magic and goes away, after the Demon Clan was sealed by the Goddess clan.

Libertation and confrontation with Meliodas
While the Ten Commandments have gotten very weak after being arrested and then released by Fraudrin, Garland excited to know that there are strong people decides to warm up and then flies off to attack the Seven Deadly Sins and others there, Garland defeats them very easily and then returns to the Ten Commandments.

Soon after Melascula along with the other Ten Commandments were confronted by Meliodas who teleported thanks to Merlin for a second, Meliodas threatened them which caused the Ten Commandments to separate.

Pairing with Garland
Melascula soon teamed up with Garland and used his commandment of faith to revive people and steal the souls of unfaithful people. However when Elaine was resurrected that it was what Ban wanted, Melascula's commandment did not work for him and apparent Elaine dies after Melascula appears and explain everything to Ban, and meanwhile Garland fights Ban, and seeing that Garland's power is superior to his, Ban then steals by beating Garland, but when Melascula realizes that Ban has stolen Garland's energy, then Melascula has attacked him by stealing his soul, but Garland devours his soul, making Melascula furious.

After that Ban's soul returns to his body, and Garland and Melascula chase after Ban, Elaine and Jericho as they reach the bar that is Escanor after Garland attacks them by throwing stones at them. Getting there Garland gets drunk and makes Melascula stay too, Garland then challenges Escanor that thanks to that Escanor turns out to be a member of the Seven Deadly Sins and being the sin of pride, Escanor then fights Garland who defeats him after doing so. Breaking her own commandments, Melascula is shocked by this, but she later shows that she didn't care much about Garland's defeat, then Melascula arrests Escanor and when she devours her soul, she almost dies causing Melascula to retreat.

Second fights against Meliodas
After Meliodas fights Drole and Gloxinia, Zeldris along with other commandments except Garland appears and fights Meliodas. Melascula congratulates Estarossa that while she asks Gloxinia to heal him that he Meliodas who has his body restored and naked, she then asks Estarossa for her to kill Meliodas, but Ban saves him by breaking her neck, knocking him unconscious.