u/Bookwhyrm

>If mortals receiving the grace of Aeons and grasping the power of Paths are viewed as a singular shattered foam, then the mighty feats of Aeons driving their Paths onwards can be likened to a towering tsunami that engulfs mountains. In this empty stellar vastness, a small number of favored mortals can also draw upon the power of the Paths with the permission of the Aeons, creating huge waves that erode the coast. They are referred to as "Emanators." While not completely subservient to the Aeons, Emanators are as good as emissaries of the Aeons' wills in everyone else's eyes.
Different Aeons have different attitudes towards their Emanators, so the degree of the power they share also varies. Some Aeons regard Emanators as an extension of themselves, and as such, generously open their Path to the Emanators completely. There are also Aeons who have no intention of creating Emanators and have no interest in worldly squabbles. Other Aeons just do as they please. It is said that Aha the Elation will randomly give mortals the power of their Path, and toy with humans according to their mood.

– Data Bank / Terms / Emanators (Phenomenon)

Since this one Data Bank entry at the start of the game we've come to learn a lot more about the Emanators, and so I believe there to be exactly two different types of Emanators; those granted access by an Aeon directly and those that are fundamentally a part of an Aeon.

I. Individuality

As the Data Bank entry states "a small number of favored mortals can also draw upon the power of the Paths with the permission of the Aeons," with the Aeons directly granting access to THEIR Path to a specific individual. This we see most clearly with Aeons such as Qlipoth (e.g. Taravan Keane or Diamond), Aha (e.g. a certain Noblesse Worm or Silver Wolf), Nanook (the Lord Ravagers), Yaoshi (e.g. Shuhu or Wingperor) and to some degree Nous (e.g. Madam Herta or Dr. Primitive).

Whether the individual in question simply followed the principles of their Path to such a degree that it attracted the corresponding Aeon's favour or simply because the Aeon wanted to (in the case of many Emanators of Elation for instance), this 'permission' THEY grant allows them to directly draw power from the Path in contrast to regular Pathstriders who only gain as much power as the Path grants them (likely in accordance to how strongly their will aligns with the Path's will).

This differs from "blessings" (to note is that this is a colloquial term since there isn't a specific one used ingame so far) granted by the Aeons in that a blessing is set in its purpose and scope, for example the blessings of longevity Yaoshi spreads or the Omniscia that Nous gifted Fu Xuan. One could argue that the one question Nous grants each Genius counts as a blessing as well, as a gift from an Aeon to a mortal.

The degree of access granted varies depending on the Aeon and the specific Emanator, with Aha for instance occasionally granting access to the entirety of THEIR Path to THEIR Emanators (as in the case with the Noblesse Worm THEY wished to make a Genius, a bit off-topic but the only known power it is implied to have had was the ability to spread joy by touch that diluted after three days).

II. Equivalency

The second, more nebulous, type of Emanators are those that in one way or another are a part of an Aeon. The most clear example we have of this are the Harmonic Strings, each known as an Embodiment of Xipe (a facet of THEM) which can "manifest on the mortal plane" through a vessel known as a "tuner" or "Chordmaster". Other than them we also have the Pure Children of Anāsrava that each have the potential to become Fuli THEMSELVES as we see with Cyrene in the Amphoreus storyline and are speculated in-universe to either be THEIR "fragments" or "manifestations".

The main theorization starts here, in that I believe among others Acheron also falls under this category, especially since IX is not known to take any active actions as the Aeon of Nihility.

>[...]
Dr. Primitive, No. 64 of the Genius Society, once asked before his disappearance: If IX is truly unresponsive to the universe, how could the Path of Nihility exist to this day? Perhaps, as the Self-Annihilators aimlessly traverse the cosmos, they are also casting the shadow of the Aeon around the universe. As for the few who can single-handedly withstand the encroachment of Nihility on their existences, their journey of self-annihilation is drawn out to infinity, and the road they walk is like a shadow of IX cast in the world.

– Data Bank / Factions / Self-Annihilators – Nihility

We know that there are countless Self-Annihilators across the cosmos, each having stepped into IX's Shadow and become cursed with self-annihilation. Yet none other than Acheron are known to be Emanators, the very concept of an Emanator of Nihility being considered an impossibility by many. Most simply waste away, their existence gradually fading into nothingness. So what makes Acheron special?

Dr. Primitive speculated that if a Self-Annihilator were able to withstand the "encroachment of Nihility on their [existence]" they would be able to draw out their self-annihilation unto infinity and that they would become an extension of IX's shadow. Acheron's existence essentially confirms his speculations; implying that by inundating her self with Nihility while still holding her existence together she became an extension of THEIR shadow, gaining access to (a part of) THEIR authority over Nihility and thus gaining access to the Path itself. (And while a little off-topic, with Acheron I personally believe it is shown that not only is an immensely strong will is required but also to follow the principles of Nihility; the acknowledgement that in the end everything will end, but even so that it is still possible to change the meaning of it.)

In summary, as the Aeons THEMSELVES inherently have full access to THEIR Path and its Path Energy, we also see that a 'fragment' or 'manifestation' of THEM can gain a part of THEIR authority and access as well.

So far I believe these to be the only two types of Emanators, but am interested how their role in the story will continue to be developed.