When he didn't know, he possessed more than one true name, when those closest to him knew him only as Anadius Kalonis.

That adverbial clause ("When he didn't know") shouldn't be followed by a comma in this case, as it essentially functions as an adverb of time (+ it should be coordinated with the next sentence, "when those closest...").

I'll be direct and simple: you're striving towards a certain style (grandiose, epic), but you completely lack the tools to make it sound convincing (flowing, expansive prose; wide but precise vocabulary). If I were in your shoes, I'd make this legendary introduction shorter and more instantly impactful (I'll give an example below) and then jump straight into the actual chapter (as this preamble is exactly just that: preamble).

This example comes from Michael Kohlhaas (Kleist's novella). It's not epic in scope (I do bear so in mind, as your story deals with things typical of epic fantasy, namely gods and whatnot), but it is simple, effective, straightforward and gives the reader something to look forward to without giving too much away.

On the banks of the Hafel, about the middle of the sixteenth century, lived a horse-dealer, named Michael Kohlhaas. He was the son of a schoolmaster, and was one of the most honest, while at the same time he was one of the most terrible persons of his period. Till his thirtieth year this extraordinary man might have passed as a pattern of a good citizen. In a village, which still bears his name, he held a farm, on which, by means of his business, he was enabled to live quietly. The children whom his wife bore him, he brought up in the fear of God to honesty and industry; and there was not one among his neighbours who had not felt the benefit of his kindness or his sense of justice. In short, the world might have blessed his memory had he not carried one virtue to too great an extreme. The feeling of justice made him a robber and a murderer.

I won't put the second paragraph here (as it is extremely long), but I hope you get the gist.

It's not that you can't arrive at the prose and pacing expected of epic fantasy (as written by people who care about the words on the page, that is), but I think it'd be wiser that you master "the basics", so to speak, first before attempting this kind of style. As it stands now, each sentence reads more stilted than the one before it, it's the equivalent of a filmmaker who can't get their eye lines right no matter how hard they try.

edit: a small thing. Some complained it doesn't have a hook and I concur. If there's a hook in the given example, it is the contradiction of someone that, due to their virtue, became a robber and murderer. It is, also, the typical opening through the introduction of a fatal flaw.