Gauntlets · Stage 21Steel Frontier硬き本能の秘境300Energy Cost26,790XP Reward900,000Enemy Base HP5,500Stage Length12Max Enemies9.4Difficulty Test your team vs this stageStage rewards73% — 減輕傷害 D: 鋼 ×120% — 減輕傷害 C: 鋼 ×16% — 減輕傷害 B: 鋼 ×11% — 減輕傷害 A: 鋼 ×1Enemy spawns (3)EnemyStrengthCountFirst SpawnRespawnBase HP TriggerNotesSir Metal Seal300%26.7s40s100%—Sir Metal Seal300%283.3s33.3s100%—Ms. Sign100%∞900s900s100%—All Island of Hidden Treasure stages