Trivis

A trivis is a complex idea of an item based in multiple timelines. To put it as simply as possible, it is an object that you put into your present by influencing your past. To start, there is a base timeline with two branches. An item, the trivis, is willed out of one branch and into the other at a point of fusion between the timelines. At this branching point, a different version of you will influence the non-primary branch to instantiate the object into the branch where it doesn't exist.

In Practice

You come back home after a long night and realize you don't have your key, you left it inside. You will your past self to have gotten the key. This takes the timeline in which you have your key and merges it in, so you spontaneously always had your key. This would normally lead to no one ever knowing a trivis could be a thing, if you change your timeline to have always had something. However, all points prior to the merging will remain intact. So, if you're out and realize you don't have your key, do things based on that change in the timeline (ex: call a friend to see if they have a spare), all of that will still have happened, though you have always had your key.

This can become infinitely more complex, having two timelines diverge so entire nations rise and fall differently. Or, it could be such that one branch goes on a quest to accumulate enough wealth to purchase an expensive Murn that is used to make a highly nutritious synthetic honey, then that murn will be brought into the timeline where that quest never happened.

Morality & Empathy

The word comes from old Humoh, specifically from a small people from the forests north of Lake Folci. It's not that the phenomenon is unique to them, there just happened to be someone particularly perceptive to time.

Normally, you wouldn't even notice you have a trivis, or give one for that matter. If you're the receiver, you just have the thing, always have. You might not know why or how, but what could you do to find out? If you lose it, the giver, the same thing.

When you part, the giver loses the trivis forever, gone from their world, which does rot. If you're in tune, you might feel bad for your alternate self. Think of it though, between the utter rarity and minuscule likelihood you'll be aware it happened, there's no point in worry. You know, I say that, but the area in which the timelines fuse, you will have both memories, you might feel some sort of way. It has happened, someone I know lost a very important photo to herself. Thief. What could you do? Try to fuse the timelines again to give or get it back?

— Witch of Knowledge

Meta

Trivis are extremely rare objects, no one has been able to willingly create one; it has only ever been observed by the testimonies of those it has already been created for. It appears that, due to the trivis being created, the two timelines affect become intertwined for a length of time afterward. There does not seem to be a reason behind its occurrence either as it has been noted in mundane things to important things. One major event where this is detailed is in the Battle of Dagjvamzha.