A brief description of the Release That Witch manga:
Cheng Yan went through time and entered a world similar to medieval Europe, becoming Roland, the fourth prince of the kingdom. But this world is not what it is used to. Witches and magic are normal here. Will Roland be able to get the throne of the king and solve the problems that fell to his share? Only his experience of modern technology and the help of witches, known as “Devil’s servants”, will allow him to succeed!