The Civil Engineer, called Doboku Shugyosha in the original Japanese version, is a miner who Ryoga Hibiki meets after getting trapped inside a cave. His appearance is based on the figure that commonly appears at Japanese construction sites.
After getting lost in some mountains, Ryoga decided to spend the night in a cave. Unfortunately a rockslide blocked the cave entrance and Ryoga's Bakusai Tenketsu proved ineffective in clearing the soft rock. Luckily the Civil Engineer appeared soon afterwards who decides to help Ryoga by teaching him the Shishi Hōkōdan. The pair then perform the technique, which successfully clears the entrance, just as the sun begins to rise. Afterwards, Ryoga takes the scroll which includes the secret to the Shishi Hōkōdan with him whilst the Engineer returns to his work.