Ko appear in Suikoden II.
During Dunan Unification War, when Tir McDohl was in Banner Village he told it to Riou as a result, Riou wanted to meet Tir but Gremio doesn't allowed it, so Ko planned to act as he was caught by a bandit to destruct Gremio. The planned worked successfully and Riou meets Tir, but the planned turned out to be real and Ko was kidnapped by a real bandits and leave him in the forest and got lost. Riou and Tir went to the forest to rescue him, they found Ko who was already poisoned by the Caterpillar. Tir and Riou defeated the Caterpillar but it got evolved and turn into Poison Moth. Tir and Riou successfully defeated the Poison Moth and bring Ko to Toran Republic's capitol, the Gregminster. There Ko was treated by the famous Doctor Liukan, Ko gained his health back and he was escorted back to the Banner Village.