Stage 3 of that quest reads: "Each Guardian enemy engages the player..."

Assuming, all three Guardians have been slain, but there are not enough quest tokens on Hallowed Circle. So the game is not finished. In the new round The Guardian's Fury is revealed. It reads: "..If there is no Guardian in play, reveal a random one, and add it to the staging area."

Does that Guardian counts towards the willpower while questing this round?

Also, the stage card has the above mentioned text; when will the Guardian engage the player. Or won't it?

While in stage 2, the Guardian engages the current first player (at time of revealing the stage card), or each round the current first player?? And if so, when? I am a bit confused right now.

On stage 3, the Guardian will immediately engage the player who has its key. So in the scenario you described, the Guardian will be added to the staging area, then immediately engage the player with its key, and will not contribute its threat to the staging area. The text on the quest card that says "Each Guardian engages the player who controls...." is passive text and always active, so it'l trigger as soon as the Guardian is in play.

When on stage 2, the Guardian will follow the first player token, and will change engagement during the Refresh phase.

Thanks.

how are you doing with this quest? I've been playing it for the past few days and have not come up with a proven strategy yet. Now I've found trackers deck and am going to try it. Love the theme cant wait to bet it!