Just one of the many times where being a human saved Iruma's ass. The only thing drained from him was his stamina, but that's all on him. Being human in Demon World comes with lots of benefits as well as disadvantages (his smell had to be masked, not having wings or mana, demons seem to be naturally drawn to him). Iruma needs to grow up fast before getting left behind. He should first learn to naturally take other demon's mana as stealthy as he could and never let the ring empty its reserves.