Mizu Zokusei no Mahoutsukai @comic

Upon being reincarnated into a fantasy world, Ryou wants to live out his days in peace with his newfound water magic. He can only conjure a cupful at a time, but it's enough to eek out a comfortable existence—or so he thought. The powers that be cast him into the wild outlands with nothing more than a humble shack, a single knife, some food...and abilities that are yet beyond his comprehension. The area is overrun by monsters and there's nary another human in sight. Ryou must now figure out how to survive above all else, but he's ready to take bulls, boars, and a whole host of other monsters by the horns if it means seizing the life he wants for himself. Each new victory brings a new challenge, but what could a fateful encounter with a headless horseman, a dragon, and a castaway swordsman have in common? They're the first steps on a grand journey that will take Ryou beyond the borders of all he knows to become the greatest water magician the world has ever seen—one adventure at a time.

(Source: J-Novel Club)