When the original four Grims were created by Crane through the forbidden magic, Winston who was the next Hawvert also wanted to create something similar to the original Grims. But the old death reaper didn't have the same powers as Crane did. He didn't have the ability to make use of the forbidden magic and the little magic that was used by him it was spells that could be used by the mortals.
Winston was never happy with it. The Hawvert wanted to be the one in the higher position. Even though he was in the higher compared to other creatures of the dead, he wasn't the one standing at the top but it was Crane. By using the little magic, and the powers he had, he pulled out a bone from his own skeleton body to create the set of Grims. These were called the second set of the Grims who came to existence, the reapers who once were mortals in the land of the living before they came to pass in the land of the dead.