For illustration, the "Adventurer's Arc" (a minimal arc which exhibits how Rimuru obtained his Adventurer's License, sheds some spotlight on how the Adventure Guild operates, and provides Elen, Kabal, and Gido some extra enlargement and screentime) isn't lined by the anime specifically, but fairly gets demonstrated in the first Opening of Season 2, exhibiting Rimuru about to head out with the three adventurers, as well as his "assessment".