They're all grouped together in the same room. It seems to be some sort of museum? There are museum-like displays, at least, on which the artifacts presumably rest. It seems that his alt's writings are also stored in the same room, which is somewhat cramped and unpretty.

Well. 

It's cool that they survived the ages, but he wants them. He experiments with making things that look exactly like the magic artifacts but aren't magic. 

Most of them he can get a nonmagical copy of. They aren't that interesting without any magic in them. Some of them would make nice paperweights.

Except for that one small pyramidal object. He can't get that one to go at all.

Huh. 

...he is going to sneak into the maybe-museum and steal his alt's stuff and try to piece together from the notes and the actual artifacts how the magic system works. He makes a scale model again to check that the place is empty. It is.

He gathers up his decoy artifacts and teleports there, invisible and inaudible.

The Archivist systems notes the unexpected displacement of an Epic-sized volume of air in the Fienus vault. No disturbances register on visual or infrared scanners, nothing in audio. Further scanning systems take an additional half-second to cycle on, but they reveal the intruder's presence. Humanoid, small, wing-like protrusions on the back. This is more than sufficient justification to engage lockdown protocols.

Heavy blast doors crash into place all down the corridor. Over each artifact, a glowing blue forcefield shimmers into existence. Warning lights begin strobing at frequencies determined to be maximally detrimental to species with human-like visual processing.

And in her office, Darth Occlus receives a priority message on her datapad. One glance, and she leaves at a dead run, waving open the turbolift doors and jumping down, not bothering to wait for the car.

Oops.

He teleports all the magic artifacts out from their newly-locked display cases and home to his planetoid, teleports the decoys into place, makes a note on the floor that says 'sorry for stealing the stuff. It's sort of mine and I won't damage it and I'll return it when I'm done. if you need to contact me you can write 'letter to Epic' and then write whatever you want to say. Any format.'

And goes home.

The Archivist records this activity, and updates Occlus when she arrives at the entrance ten seconds later. She goes to inspect the Fienus vault in person.

These replicas are all uncannily accurate. If they weren't all completely inert, she'd be unable to distinguish them from the real ones. The note is puzzling. What sort of thief competent enough to thwart her security and create near-perfect decoys leaves an apology? And what does 'sort of mine' mean? Darth Fienus lived almost nine hundred years ago, he has no living descendants, she is the only person in the galaxy to have anything like a claim on his relics.

She leaves the Archivist on heightened alert and returns to her office to review the security logs of the incident. All the artifacts blinked out while the ray shields were active, all at the same time, with no indication that the shields were even mildly stressed. She has the Archivist run a test on the shielding systems. They're all functioning normally. She's missing something, here.

Occlus opens a new file on her datapad. Title: "letter to Epic".

I do not know who you are. I do not know why you believe yourself to have a claim on the artifacts you stole. I do know that if they are not treated with care, some are exceedingly dangerous. If you get yourself killed before you effect my artifacts' return and I must retrieve them myself, I will not be pleased. If you are truly so insistent that you must study them immediately, we can discuss terms whereby you can do so locally, under observation.

He conjures his mail every few minutes, nervously.

There are alternate universes, he writes. I'm an alternate universe version of him. I'll accept help studying them if you're offering it.

 Scale model of the person who wrote the note. Scale model of the surroundings of the person who wrote the note. Invisibility and inaudibility obviously didn't do it last time -

Well, he'll just have to be quick. Pop, note on her desk, pop.

Occlus, unnervingly, manages to look directly at him in the brief instant he is present.

Your explanation is highly implausible. What evidence do you have?

Does this universe have FTL communications? This method is annoying. And I am powerful enough to fake any evidence that you might find convincing if I wasn't around being powerful enough to fake it. Are you a historian? I can bribe you really well if so.

Pop, note, pop. 

I would not trust a conversation of this sensitivity to the Holonet without paired encryption. It will take a brief while for me to acquire such devices. 'Historian' would not be a complete descriptor, but it is a part of what I do.

I can make arbitrary matter. "a data drive containing the complete written works of the alternate universe version of me in this universe" counts, and when I made myself one I got Fienus's notes. Name something and I'll make it for you to prove it.

A CN-12 targeting chip.

He goes out into vacuum in case it's dangerous and then tries making one.

It's a fiendishly complicated piece of nano-circuitry with embedded programming. It doesn't, by itself, do anything.

He drops it off in her office with another quick in-and-out.

Well then. It certainly looks correct. She hooks it up to her datapad and runs some diagnostics. It appears to be fully functional.

I accept your premise. Your half of the holocomm is on my desk, you may retrieve it at your convenience.

He does that.

When Occlus sees it disappear off her desk, she initiates the call. It doesn't go through.

For it to function, it will need to be within range of a Holonet transceiver. That is, within the galaxy.

A minute later another pop note pop.

Okay, I built myself a planetoid in your galaxy. Don't know how to call you.

Occlus will take care of that.

The button at the base of his comm begins flashing softly.

He presses it.

And up before him pops a miniature holographic image of Darth Occlus, who likewise is presented with one of him.

"Hello. I am Darth Occlus, member of the Dark Council and head of the Sphere of Ancient Knowledge. Who are you?"

He looks like a seven-year-old. He has very long neatly-braided hair and pointy ears.

"Like I said, I'm an alternate universe version of Fienus. I go by Epic but my name is Fëanáro, all alternate universe versions of me have similar names - there's a Fannar and a Firayar and a Ferardrin - I just landed here and I have a lot of magic and haven't decided what my ambitions are yet but knowing what my alt was up to will help. Is the supervillain aesthetic on purpose?"