I'll preface this review by saying, "The story has potential." And my opinions are subjective.
It's the author's first work and, it shows.
I read all the free chapters available. Definitely recommend reading them all before deciding if it's for you.
Personally, I urge you to give it a try. It may be to your taste. I wouldn't know.
Writing Quality: The writing quality went up during the last chapters. But there are still glaring problems. The prose doesn't flow smoothly. There are syntax errors, and sometimes the words are used inaccurately. (Not their first language, acceptable. Like me ;-) )
The author sometimes misspells character names, even the MC.
There are minimal descriptions, lending no credence to the setting. The ones that are there, vague and opaque. They don't give you a sense of space.
The story and its pace feel choppy at times. Things are happening. Constantly. The story is in motion, which is good. But it gets stale very soon. It's monotonous. Athan did this. Athan gained this. Athan comprehended this. Athan went here and did this. It felt like the author was in a hurry to get the story moving and get to what he actually wants to write. Most of this can be fixed in editing.
Stability of Updates: I read after the chapters were locked, so I don't know what the update is like. So, I'll give it 5 stars, assuming it's stable.
Story Development: The author seems to be aiming at something. I assume he has things planned out for future developments. Wonderful.
But. There wasn't much conflict or an obstacle for the MC. The first real complication that remotely mattered was maybe Tiana being trapped (and conveniently beneficial to her in the long run). It was a complication introduced solely to establish a plot point, gee-whiz, for later developments.
The first volume was a speed run for the MC. Like running through the tutorial of a game, not the actual game. The story has potential, and developments are looming over the horizon, but getting there might be a chore.
I couldn't clearly pinpoint a story promise(except the usual, OP, harem, basically, tags). It does have a story goal for the MC. But I don't think it can carry the weight of the novel. This likely will naturally come out later in a more developed fashion.
Character Design: None of the characters are fleshed out. They don't have a unique voice. I believe they will find it during the story's run. It's in its infancy, after all. Up till chapter 102, Avelia seems deeper than the MC.
We don't get to spend enough time together with the characters to get to know them. The story is a linear progression from one point to another. Most of the time we spend with Athan(the MC) is him gaining power or in the process of doing so. The dialogues are straightforward, with most of them sounding the same.
World Background: It's clear that the author has thought about the magic system and the world. He has developed a wonderful world, but none of it shows as there is no vivid description of the places they visit. It would be better if he showed off some of it in worldbuilding descriptions rather than frequently info-dumping on the magic system.
He has thought a lot about his magic system, which may be a negative here. There is too much in-between it takes so long to build anything up. Leaving us with the monotonous Athan did this and that scenes/chapters. This is exacerbated by the lack of meaningful conflict. Leaving much to be desired by way of dynamicity to the story.
I'll state what I couldn't articulate or think I didn't convey clearly here.
Writing - It will get better as the author does it more, so it is a minor problem for a new writer. Still, an editor would be a good choice if the author can't spare time for it.
Characters - We should get more time together with the characters. Learn about their inner self, their wants, fears, and ambitions. Especially for the MC, he needs to be thinking more, informing the readers about himself more(no melodrama monologues).
The character of Tiana, for now, is no more than a showpiece. It doesn't affect the story in any way if she was completely removed from it. She didn't add any value by being with the MC. She didn't change him, nor did she create complications or conflicts for him. Her initial problem got resolved off-hand, which was a wasted opportunity to develop her character. Her coupling with the MC was also a bit forced. She felt like a starter pokemon equivalent of a harem in the MC's quest to catch 'em all. Then there is the situation of her being trapped. It was not the least bit impactful. The whole situation being a boon for her also didn't help. It introduced the MC's gee-whiz item, but so what? We would've found out about it when he climbs 2 realms anyway. It served no purpose. Other than giving the useless character just what she needs to be relevant for the rest of the story(No hate for Tiana). And an impetus for Athan to hurry up through the realms, which he would blaze through either way.
Also, some descriptions and concrete details would be an immense boost for the story. There was no imagery in my mind's theater the whole time I read the story. I could not for the life of me imagine a scene where the story was taking place except for a vague idea of what it might be like.
Lastly, I think the story is stretching thin, not by the author's intention but due to the nature of the story elements themselves. The detailed magic system and the impressive line-up of intents and elements give a sense of vastness to the world. But it may pose the risk of creating a plot hole or inconsistency in the later stages of the story. The author can play in a wide area but, it will limit the depths he can explore. Creating hidden problems that will come back to bite at the most unexpected of turns. My suggestion would be to limit the scope and focus on digging deep with the pieces at hand, making the story richer in substance than cool in variety. Compressing the plot by mixing them and running them in parallel or sub-plots might help. I don't know if I made sense.
If I came off as pessimistic(I definitely did, didn't I?), that wasn't the intention. All the power to the author. Keep up the good hard work. You have a lot of potential with this story.