Spellsong (呪歌, Juuka) is a Yellow keyword, possessed only by The FleetingDarkPrincess Rias-Urovorun. The keyword is based on Spellbind, the keyword of Rias-Urovorun's motif, The DragonTwelveGodKing Ourovorius. It reads:
- Spellsong - (Opponent's Turn) While you have a "Song" Magic card on your Field, at the start of each Step of your opponent's turn, return one opposing Spirit with equal or less BP than this Spirit to the bottom of the deck.
While Spellsong offers deck bouncing instead of Spellbind's core removal, both effects share the characteristic of activation at the start of each of the opponent's steps.
Although somewhat hindered by Rias-Urovorun's mediocre BP, Spellsong is a very powerful effect capable of both clearing the opponent's Field of many Spirits and limiting the opponent's resources.