It's time I settle the debate that has either been talked about or been dropped. The Artifacts are simply Spirits that the characters themselves cannot see.
Also they have a corresponding El Type (Exception of Karte) as we know of course. Fire, Water, Earth, Sun, Wind, perhaps Moon perhaps not either, and then Neutral (Which I'll assume neutral is like Ain being an Angel, and his fight goes towards the manifestation of Ishmael.)
While this sounds off because "NOAH'S MASTER ROAD IS ALSO TALKING WITH HARNIER YOU DUMMY!!! SO HE DOESN'T GET THE MOON ARTIFACT!!!"
and tbh, that does sound correct, the Moon artifact does not seem to 'exist' or if it did, it's an indirect existence with Noah since the artifact itself doesn't change with Noah.
and no El Type or Null, would be Karte or at least you'd assume that well Add and Eve should be seeing their Artifact, it's a machine that somehow appeared. And that's the thing, it acts like any of the artifact brethren it is a creature that also appeared during the Harmony Festival.
Look at the Spirit Stone Wedge. 'Spirit' meaning ingame mechanics does confirm that the characters don't notice their existence despite that we the player influence their stats and growth, we gain exp, they gain exp and grow.
Now I want to add the elephant(s) in the room.
Lu and Laby. While we don't know where specifically Laby came from 'somewhere in the demon realm', aside living in the Black Forest. and Lu appearing before Ciel in Lanox/Ranox. I'd like to point out the question that is,
why do they both get Elrios Artifacts? I'd like this chance to say, the El chose them.
As we don't know much about the Dark El that Henir's Order has if it has the same ability as the Primal El to create artifacts for individuals.
Now if this is the case, does this mean we'll fight Dandelion with an Artifact that is influenced by the Moon and the Dark El itself? idk. I'm just curious as to the fact the Moon Artifact doesn't seem to exist and it makes sense storywise.
Will we get a single character who gets this one particular Artifact? Who knows.
Why am I excluding Noah from the 'Moon' when our boy literally has the Moon system? Because his Artifact is associated with Harnier just like Ain's Artifact, they both got the same symbol thus the artifact is not Moon related.