AoE2 Codex is a free, fan-made companion for Age of Empires II: Definitive Edition, organized into two parts.
Play Castle Daily, a daily AoE2 puzzle; solve the Upgrade Maxing upgrade puzzle; and rank unit matchups in Counter Call, a counter puzzle.
Browse every civilization in The Civ Codex; plan unit upgrades with the Upgrade Codex tech planner; and resolve fights with the Battle Sim battle calculator.