Shield Guardian's Spell-Storing ability

[zarberg]

Under the Shield Guardian's listing in the SRD it says the following:

"Spell Storing (Sp): A shield guardian can store one spell of 4th level or lower that is cast into it by another creature. It “casts” this spell when commanded to do so or when a predefined situation arises. Once this spell is used, the shield guardian can store another spell (or the same spell again)."

It's the "predefined situation" that I have a question about; Can this predefined situation arise when it is not the Shield Guardian's initiative, I.E. can you store a spell to be a death-blow of sorts where it activates when the Shield Guardian reaches 0 hit points?

 

[Plane Sailing]

I'd say no. I read that as

"It casts this spell" - under a couple of conditions - either "when commanded to do so", or "when a predefined situation arises".

Thus it might have "see invisibility" stored, and it will cast it if the situation "you are attacked and you cannot see any opponents" occurs.

It is not phrased as if it is a contingency spell style activation, and that is the only way I'd have seen it working on someone elses initiative.

(n.b. we recently fought one that rather wickedly had "fire shield" stored in it. You don't want to fight a shield guardian that is protected by fire shield!)

 

[LordAO]

I agree with Plain Sailing. The fact that it says "it casts" the spell means to me that it must take an action to do so.