sakuretsu and magician's circle

[bigdevilyogi]

If I attack with mystical elf and my opponent tries to play sakuretsu armor, what would happen if I chained magician's circle?
If he has a spellcaster in his deck, would sakuretsu not be able to resolve and be destroyed? If he doesn't have a spellcaster, I assume I just special summon a monster and mystical elf dies.

 

[Dillie-O]

Oooh, that's kinda fun and tricky all at the same time. Let's build the chain and resolve it.

Chain Link 1: Sakuretsu Armor
Chain Link 2: Magician's Circle

Let's note that both activations are valid, since you are still responding to the declaration of an attack. Some people may think that Magician's Circle got bumped out, but that's not the case.

Now lets resolve:

Resolution 1: Magician's Circle resolves and both players special summon a Spellcaster to the field. Technically a replay is now in order, but we have to finish resolving the chain.
Resolution 2: Sakuretsu resolves and destroys the monster that declared the attack (Mystical Elf).

As mentioned above, a replay technically occurs because a potential attack target appeared on the defenders side of the field, but the original monster that declared the attack was destroyed, so things progress as usual.

Hope this helps!

EDIT: Rereading your post, I forgot to mention, that you are right on the second manner. If your opponent doesn't have a Spellcaster to special summon, then you get a bonus monster and your Mystical Elf dies.