Interesting. So gaia is unreachable to every godhead?
Most likely, given she created the Triat, given she created the Wyrm, who is the Void itself.
I believe uldmaster told me that Gaia is greater in power than Bondye
They're about equal, I wouldn't be able to say definitively who is stronger, since they're both extremely impressive.
I still don't understand how epiphamies and etherspace work. Could you explain it to me? Is etherspace baseline high 1-A?
So, the Epiphamies are at the top of the High Umbra, they're these vague extremely abstract realms which are more like clouds passing by the Mountains that are the Spires.
They transcend concrete reality, they are neither the same nor do they appear in any one fixed location.
Etherspace, also known as the Horizon is beyond the Epiphamies.
The Umbra is a shadowed reflection of Earth, so the Spires are the Earth's "mountains", Epiphamies the "clouds" and Atmosphere while the Horizon is beyond the Atmosphere, into the Shadowed reflection of Space.
In the Horizon are the Shard realms, the Umbral Version of each of the Planets, each of which has a corresponding Godhead/Celestine who is the Embodiment and Manifestation (for example, Luna, the Celestine of the Moon, if she were to somehow super perish, the Moon would disappear alongside her).
They (the Planets) embody one of the Major spheres of Magic from Mage, for example, Saturn embodies the Sphere magic of Time. This means that travelling to Saturn is a serious risk, as once you enter the realm, you are no longer walking around space but instead time, taking any movement could lead to you going into the past or future, or maybe another time all together.
Also has any other god in the verse (aside from Bondye) any statements of being unreachable or unaccessible to other gods, characters or cosmology?
The One Giver from Demon the Fallen (Secondary Canonical material/Non-Canon material) says that the Angels cannot approach her, that to even speak to them would destroy them, and only the strongest can receive a filtered down version of her words.
Thus she uses the Highest Angels of the Highest House to be her chosen messengers, who relay her message to the other Angels as to not destroy them.
She is likely the closest, but Angels (DTF) are not the same as Angels (oWoD), so it's hard to say how impressive they are.
Angels (DTF) could be Low 2-C, or they could be upwards of 0.
Also what is the black diamond? Is it beyond tellurian? Is it contained withing the void? And what tier would it be?
I actually plan to make a profile on the Void, which covers this topic.
For a full explanation on what it is, read further
here.
What is "the throne of Thaumiel"?
The Throne of Thaumiel is the final descent into the Qlippoth.
As you continue to descend into the Qlippoth, you will eventually reach the opposite of Keter (Crown).
There you find Moloch and Satan (An Aspect of Lucifer) guarding the Throne with Lucifer sitting upon it. Lucifer will allow the Nephandi who has reached that far to sit upon the Throne and achieve the Black Diamond.
Also one last question: is consensus hierarchy contained in the void or completely outside of it?
There's two ways to go about it;
Either the Void is the end of the Hierarchy, as Book of the Fallen states it's the End of the line, there's nothing after the Void. You've reached the Absolute.
Or, that Book of the Fallen is written by an Unreliable narrator (which WoD books are often written as) in which case, the Void is a part of the Mage consensus, and it exists because Nephandi believe it does, and it works as highly as it does because they believe it does.
Thus, it's within the Mage's consensus, simply representing the end/edge of it.