In the One Year War, Slender went on a recon mission to Side 7 with Gene and Denim under Char Aznable. Slender stayed behind near the exit of the colony to stand guard while Denim and Gene went further into the colony. After Gene's outburst attack, Slender sent a report to Dren and Char and was the only one of the three to escape after Amuro Ray got into the RX-78-2 Gundam.