ARENA (Adaptive Reseeded Elimination for Novel binder Architectures) is a tournament-based meta-exploration wrapper around Protein Hunter (Boltz-2 + SolubleMPNN). Protein Hunter is a compute-light iterative co-design pipeline, but is strongly seed-dependent — initial random seeds determine the structural basin, and poor seeds rarely recover. ARENA solves this by launching many independent seeds per epitope combination and applying progressive elimination during generation, not after. This invests compute proportional to observed promise (analogous to successive halving in hyperparameter search), exploring 2.3× more structural basins than running equivalent compute as full trajectories.