RUMBLE: orb of eternity

The story is about a boy unlike others, was summoned to another world by the demon lord, his purpose was to find rumble which is the orb of eternity, which has the ability to do anything and all things, so they could revive the demon lord's wife, ripple who was murdered by the humans, he embarks on a journey together with the demon lord's children to find rumble so they could bring back their dead mother