God's Disciple; Other World Traveler

Summoned by the God's to help assist them in rescuing worlds for them, as a test and an opportunity he is placed in the world of Therin a C Rank disaster world with the help of a custom system given to him and a few skills he can select, he is given a mission to defeat the demon lord before being transported to other worlds to rescue worlds alike and assist the god's. In exchange the god's will protect his earth family till they pass away of old age and continue to protect their blood line as well as allowing him to freely travel to worlds he has been to already when not on missions.