Does the Celestial Armor require medium armor proficiency?

Question

TL;DR: Does the Celestial Armor require medium armor proficiency?

I found the Celestial Armor which said that it is a medium armor Chainmail+3, and is light enough to be considered as light armor.

But, does it work just like a Chainmail made from Celestial Mithral, which then makes the armor light enough to be considered as light armor, but still requires medium armor proficiency? After all, it does seem to be made from it, even if it doesn't state it.

When checking other armors, I found the Elven Chain which state that it is a Chainmail, but should be considered as light armor, even from the proficiency point of view. But it also state that it is made from Mithral unlike the Celestial Armor.

Answer 1

Paizo creative director James Jacobs in a 2010 Paizo message board post, in part, says

Celestial armor is not mithral—it's actually made of silver or gold (as mentioned in its description), and thus doesn't gain any of the standard modifiers for being mithral at all. It's its own thing. Its lower arcane spell failure and higher max Dex bonus are a result of its magical qualities, not what it's made out of. In addition, this magic allows folks to wear it as if it were light armor—the mithral versions don't do this because mithral isn't fundamentally magical like the enhancements on celestial armor.

Thus, according to Jacobs, this FAQ entry on proficiency with mithral armors doesn't apply to celestial armor, making it so folks who are only proficient with light armor can wear the celestial armor normally.

While not a rules guy, Jacobs frequently fields technical and not-so-technical Pathfinder questions, and his opinions often carry at least some weight with fans. Even if such opinions aren't officially official, they're often the best fans can expect.

Answer 2

No, Celestial Armor does not require medium armor proficiency.

Compare these texts:

From Celestial Armor

It is considered light armor.

Versus from Mithral (my emphasis)

Most mithral armors are one category lighter than normal for purposes of movement and other limitations. Heavy armors are treated as medium, and medium armors are treated as light, but light armors are still treated as light. This decrease does not apply to proficiency in wearing the armor.

In otherwords, Mithral medium armor acts like light armor in many ways. Celestial Chainmail is light armor.

(I think James Jacob's explanation--quoted in another answer--is helpful, and agrees with this conclusion, but in this case the written rules themselves are a more primary source.)

Answer 3

It does not say it is light enough to be considered light armor. The text clearly states that it is a light armor.

It is considered light armor

Therefor you don't need medium armor proficiency.

Answer 4

Yes, you still need medium.

Located under the special materials rules for mithral in the FAQ

Most mithral armors are one category lighter than normal for purposes of movement and other limitations. Heavy armors are treated as medium, and medium armors are treated as light, but light armors are still treated as light. This decrease does not apply to proficiency in wearing the armor.