Unholy Knight
The sins confront a strange demonic being. Meliodas is about to deal the final blow when he loses heart and stops attacking. In the meantime, Elisabeth discovers some facts about Meliodas's past. In the end, Elizabeth rushes to the battleground and her words give Meliodas the courage to fight to his full potential. When the sins inspect the dead body of the monster they find out it was some kind of hybrid between human and demon.
Aired 25/01/2015EP 15 - Unholy Knight
The Seven Deadly Sins
When they were accused of trying to overthrow the monarchy, the feared warriors the Seven Deadly Sins were sent into exile. Princess Elizabeth discovers the truth - the Sins were framed by the king's guard, the Holy Knights - too late to prevent them from assassinating her father and seizing the throne!
Now the princess is on the run, seeking the Sins to help her reclaim the kingdom. But the first Sin she meets, Meliodas, is a little innkeeper with a talking pig. He doesn't even have a real sword! Have the legends of the Sins' strength been exaggerated?
(Source: Anime News Network)