Negates the effects of your Effect Monsters / Destroys your face-up Monster Cards
Special Summons from your Graveyard
Prevents your monsters from attacking
Hmm... when the Mermails are destroyed by this card's effect, can they still active their effect after they're sent to the GY? Sometimes when a card says "their effects are negated", it only applies when the card is still on the field. If the Mermails can still use their effect once they're sent back to the GY, then this might be a good recovery card.
Dang, I didn't realize Abyssgunde says "discard". That obviously wouldn't work. But Abysshilde's "sent to GY" should work, because they go to the GY after destroyed. Still, Abyssgunde's effect is what I was aiming for, so I guess this isn't a good recovery card after all.
Sent to the GY isn't the same as being destroyed, but being destroyed (and not banished) will usually result the card being sent to the GY, thus triggering the "sent to GY" condition (if it doesn't care HOW it is sent to the GY). And yes, if Abysshilde is destroyed by battle (and not banished), then her effect would trigger too. (Think Kidmodo Dragon.)