During their two-month contribution to the rathena/rathena repository, Kaifa focused on resolving complex gameplay bugs to enhance stability and user experience. They addressed an edge-case in C++ where the Back Stab skill’s targeting logic failed when caster and target occupied the same cell, updating the algorithm to compute relative positions accurately and ensure reliable casting in Renewal mode. Additionally, Kaifa corrected YAML-based item combo logic for the Frontier Rune Crown and Abyss Dagger, fixing skill attack bonus calculations under specific conditions. Their work demonstrated careful attention to regression risk, clear commit traceability, and a strong grasp of backend game development.