Estarossa

Race: Demon

Gender: Male

Birthday: January 14

Height: 200 cm (6'6½")

Weight: 95 kg (209 lbs)

Hair Color: Silver

Eye Color: Black

Blood Type: AB

Estarossa is a demon and member of the Ten Commandments, elite warriors of the Demon Clan handpicked by the Demon King himself, but was sealed away in the Coffin of Eternal Darkness until he was set free.

[Spoiler] Estarossa's true identity is revealed to be Mael, the strongest of the Archangels. 3000 years ago, as a way to end to the Holy War, the demon Gowther used a forbidden spell and reforged Mael's memories, and the memories of everyone who knew him, giving him a new identity as the second son of the Demon King, under the name of "Estarossa".

Now a part of the Demon Clan, Estarossa received the Commandment of Love that Meliodas abandoned, becoming a member of the Ten Commandments. The supposed death of Mael was so devastating for the Goddess Clan, that it forced them to carry out the seal of the Coffin of Eternal Darkness. Estarossa was sealed away by the Goddess Clan along with the rest of the Demon Clan, ending the Holy War. [/Spoiler]

(Source: Nanatsu no Taizai Wiki)