Ryouchi Bouei Rawkuma - Okiraku Ryoushu No Tanoshii

The next morning, the orcs slip, slide, and get launched into a holding pen by automated catapult nets. Laz gives a thumbs-up. "See? Fun defense."

Laz notices a horde of orcs approaching from the eastern forest. Instead of rallying knights, he spends three hours designing a "slime-powered mudslide." His commander shouts: "Lord Laz, they’ll be here by dawn!" Laz yawns: "Good. More time to add a water slide."

The story follows , a reincarnated individual who wakes up as the young lord of a small, forgotten border territory. Monsters, rival nobles, and demonic invasions are constant threats. But Laz doesn’t panic. He doesn’t raise massive armies. Instead, he approaches defense like a sandbox video game: experiment, automate, and enjoy the process.