Will and Mutual Hatred

Mutual Hatred: Dark Virtue Battle: Target your unbowed Samurai: Target an enemy Personality. Before this battle's resolution, destroy both targets if they are opposing each other.

Will: Dark Virtue Battle: If you control an opposed unit at the current battlefield, target your dead Samurai Personality: Bring him into play there, paying 2 less Gold and ignoring Honor Requirements.

I have searched the FAQ, but I may be looking for the wrong thing - I don't know if Muitual Hatred is Ongoing, or Delayed, or Triggered, sorry.

My question is this: If I play Mutual Hatred, targetting my samurai and theirs, my opponent responds by destroying my samurai, and I follow up by Willing the newly murdered samurai back into the battle, and then we pass until Battle Resolution - does Mutual Hatred still trigger, as they are opposing each other at battle resolution? Or has the destruction of my samurai prevented this, even if he comes back?

Many thanks!

The effect of Mutual Hatred is delayed; it has a specific time point stated in the future when it will occur (if the condition is met).

The fact that your Samurai has died and returned is immaterial. A card that is destroyed will not "forget" ongoing or delayed effects upon it unless it both leaves play AND becomes face-down. So, if at the given time point ("Before this battle's resolution"), the condition upon Mutual Hatred's effect is met ("they are opposing each other"), then the destruction will occur.

(Technically, the effect of Mutual Hatred doesn't even end if the Personality becomes face down and out of play: it's a delayed effect that still attempts to trigger "before this battle's resolution". However, if either Personality has gone face down and out of play, game state loses track of which Personality was targeted by Mutual Hatred, so the condition "if they are opposing each other" cannot be satisfied.)

One further thing of note:

There is no such thing as a "triggered effect". Reactions have triggers, which you may respond to by taking that action. And some traits have triggers, which cause their effects to activate. But "triggered" is not a descriptor of an effect itself.