Shiranui Spectralsword (HISU-EN041) [Hidden Summoners]

If this card is in your Graveyard, except the turn this card was sent to the Graveyard: You can target 1 non-Tuner Zombie-Type monster in your Graveyard; banish both it and this card, and if you do, Special Summon 1 Zombie-Type Synchro Monster from your Extra Deck whose Level equals the total Levels those 2 monsters had. You can only use this effect of "Shiranui Spectralsword" once per turn.