did you discovered who or what that presence was?,

discover, remove the .

The change was so subtle that didn't noticed at first, it was only when his voice changed to a silken, honeyed almost sultry tone that could enthrall anyone regardless of gender or species, did they noticed that he, now a she, was not the same as before.

Better to say
The change was so subtle that they didn't notice at first. It was only when his voice changed to a silken, honeyed, almost sultry tone that could enthrall anyone -regardless of gender or species- that they noticed that he -now a she- was not the same as before.

that demonstrate his, now her, mastery of magic.

demonstration

“The Infinity Gems or Stones are artefact of great power that exist in the universe since the Big Bang,

artefacts
It should also be noted that -as far as i'm concerned- an artefact is a relic of a long-gone civilization, or something similar. An artifact is more like a powerful magical item that existed for a very long time, but still reains its power or significance.

“Actually, that make sense and also answered a lot of questions that I had," said Celestia remembering Candace ascension to alicornhood.

makes, Cadence's

“Once a being archives the status of a demigod the prayers of your worshipers empowers you further and gives you additional powers besides you original ones," added Loki before getting up and walking to the entrance of the dining room.

achieves, worshippers, your

Putting the book on the ground in front of her and she starts to read it.

no need for that and

Also, too. Many. Commas.

8116921
Sorry about the mistakes, still without a proofreader.
Are you interested in be a proofreader for this story?

8116921
Also

artefacts
It should also be noted that -as far as i'm concerned- an artefact is a relic of a long-gone civilization, or something similar. An artifact is more like a powerful magical item that existed for a very long time, but still reains its power or significance.

artifact
noun [ C ] UK ​ /ˈɑː.tə.fækt/ US ​ /ˈɑːr.t̬ə.fækt/
​US spelling of artefact
Source

8116921

Sorry about the commas, we use them a lot in portuguese (my native language).

8116921
I tried the ‘Proofreader Group’ but all the ones tied were either too busy and declined my request or didn’t respond at all.
The only one that accepted my request said he would do it but after that he didn’t respond to any of my messages, that was a week ago.
I was about to post a request for a proofreader on their forum when I saw your comment and it reminded me of your offer.

8117196
1) I have made the offer to several others.
2) I said "as far as I'm concerned". It's a good way to separate the two definitions.
3) I can understand that.
4) If you need it, I'd be glad to provide it.