How does eh/ehq express character?
Don't get angry immediately, it's genuine question. I don't understand all this weird pronouns stuff that I see on the English internet, especially on Tumblr. I don't have it in my native language.
You're not! The way you're seeing it is perfectly fine, some people care about it more than others and neither are really wrong- for example, i use it/its pronouns because that's just what makes me feel happiest but i don't mind if people call me by something else while done people would care a lot more. My pronouns are more like an aspect of me vs a representation of my whole identity
(I apologize for the wall of text ;-;)
Pronouns are an essential function of just about any language. A pronoun is basically just a noun referring to a person (bit more complicated but yeah thats the gist). He, she, they, we, it, etc are all pronouns. There may be languages out there with limited pronouns, or who express things in a different way, but most languages I am aware of has them in some form. They are not always gendered however.
In english, several pronouns imply gender. For example "she" implies a female gender to the person being referred to. This creates a problem, as transgender and gender nonconforming individuals are uncomfortable when they aren't seen as the gender they identify as. Thus the concept of changing one's pronouns, and introducing oneself with their pronouns. This is merely a tool by which to ensure that the language we use to identify each other does not accidentally hurt anyone. Its basically the same level of respect as not calling someone a nasty nickname.
This works great, for some people. He/she/they are all very useful pronouns and can be applied to a wide variety of identities and genders, but some people don't really feel like their identity fits within any of those boxes, and they want a new box. Or heck, want to be outside any box. Thus we come to the concept of neo-pronouns. Essentially newly invented pronouns used to describe people who don't feel represented by the "standard set". A lot of people who don't fit in the binary of he/she use "they" instead but that doesn't feel right for everyone. Some people feel more comfortable with a unique singular pronoun instead.
And, finally (apologies for the rather long wall of text, I just wanted to be thorough), we come to eh/ehq. Eh/ehq are examples of neo-pronouns. They're not ones I am familiar with personally, but in essence they express something outside the gender binary. Choosing these pronouns can express character in a lot of ways, especially for an immortal born-from-the-fabric-of-the-universe god like the MC is in Uroboros. It can express an alienation from conventional gender norms, a desire to distance oneself from those norms, a simple sentiment of not caring all that much about gender and preferring to be unique in one's expression, or all of the above, or none of the above.
Eh/ehq, in essence, expresses that the person using them is not male or female, does not wish to present as such, and does not wish to be perceived as such. The reasons for this can be numerous but that is the essence of it.
And bringing back around to the topic of languages. There are languages out there that don't have gendered pronouns, or have less of an emphasis on gendered pronouns. It sounds like you likely speak one of these languages. I imagine it might sound rather silly for english speakers to get all worked up about them lol, but it is just a matter of expressing one's identity. Its also worth noting that not all pronouns refer to people. "This, That, and Those" are all pronouns as well. Again, most languages have pronouns, but only some languages have gendered pronouns and as such using the proper gendered pronouns may be more/less important depending on your language.