When some initial attempts to free Veldora the Storm Dragon fail, Satoru decides to envelop him in his stomach, but not before they give each other names: with Satoru being named Rimuru Tempest and the dragon Veldora Tempest. It works: the dragon is no longer a prisoner of the spell, but nor does he have physical form anymore. Rimuru, however, knows he’s in there somewhere.
For the next few weeks Rimuru sets to work gaining new skills, some of which he gains just by performing a new task; some of which he takes from the various beasts he defeats. It’s a very procedural sequence but it’s well-paced and always satisfying when he slays a new foe with the skills of the previous one.
In this way he gathers quite a bit of power, and eventually reaches the front door of the cave, which to his surprise opens to reveal three human adventurers. Rimuru slips out without them noticing, and the “disappearance” of Veldora changes the balance of power in the entire region.
For instance, Rimuru assumes Veldora, or at least his power, kept direwolves away from a village of (non-rapey!) goblins, whom are extremely frightened of the slime due to the intense magical aura he’s emitting. It seems even sealed away Veldora cast a big shadow in the area.
Rimuru hears out the goblin elder and decides to help out, considering how hopeless their fight is (there are only 60 goblins to 100 wolves, each of which requires an average of ten goblins to defeat, so they’re at least 940 short). In exchange, the villagers offer him their undying loyalty.
And so, not long after befriending and then absorbing a tsundere storm dragon, the Slime has now become a goblin leader. Never a dull moment here on TenSura.