When a "Cipher" monster or "Cipher Soldier" you control is destroyed by battle and sent to your Graveyard: You can discard this card; send 1 card from your hand or field to the Graveyard, and if you do, Special Summon that destroyed monster. Once per turn, during the End Phase, if this card is in the Graveyard because it was sent there this turn: You can add 1 "Cipher" card or "Cipher Soldier" from your Deck to your hand. You can only use this effect of "Cipher Mirror Knight" once per turn.