Abel to Makai no Ou

The grand fantasy adventure manga centers on Abel, the second prince of a kingdom. He is kind-hearted and well-loved by the people, but his older brother, the kingdom's first prince Strain, does not like him and treats him harshly. One day, a demon appears in front of Abel and tells him that he can make all of Abel's wishes come true, if he forges a contract with him. Abel declines the offer, but he is forced to get involved with the demon after a major incident. (Source: ANN)