This was Mashima's first long manga and... it's bad. This review will have spoilers but I'll warn you beforehand. Without spoilers I won't be able to justify how bad this manga is.
Visuals:
1) the art style is very simplistic but some panels are confusing to understand in my opinion. However they became better later on.
Story and characters:
1) MINOR SPOILER: For the storyline where Haru gets told by an old lady that Elie will die regardless, it would've been much better to have the lady show him that he'll stab her with the rave sword. It would've kept the mystery for way longer and the reader would keep guessing for a longer time
2) sexism is NOT amusing, interesting or entertaining
3) corny as fuck all the time
4) the mangaka sets a bunch of rules and then breaks them just to help the main character whenever he can't think of anything clever, which is often. One of the examples of this is in chapter 115. ***********SPOILER************There's this character that can shatter anything he touches. This character has been shown to be CLEARLY touching the floor and nothing happens. Eventually the main character pushes him against a wall... And because this character touches the wall, it breaks and he falls, making the main character victorious.
5) too predictable to be enjoyable
6) *********SPOILER****** Chapter 161: after being shown that there's a full blown war going on with people killing defenseless victims and laughing at them, Haru is the only one bothered by it and wants to stop the war immediately. Elie then tells him to smile because if they smile, the other people (the ones being slaughtered) can smile, too! Haru agrees with her and both smile like nothing's happening. I can't even.
7) *******SPOILER******* Chapter 206: there's a plothole regarding who can use the Etherion. This chapter exists after Elie and her allies being aware that she's the only one capable of controling Etherion. BG had already tried to kill her, even after obtaining the magic staff. However, in this chapter it's revealed that they aren't sure if they can find someone else capable of controling Etherion. The leader of BG decideds to kill their best candidate and once that fails, that's the moment they realize that they don't need Elie afterall, which proves that they wouldn't try to kill Elie before as they wouldn't be sure that they could use someone else besides her. On chapter 216 it's revealed that Belnika actually tricked Hardner into believing that she could indeed use the staff. It's just a mess of a plotline, honestly.
Look, I can summarize this manga like this: there's 296 chapters + 2 extra stories. Out of these 298 chapters, I only enjoyed 22 of them. This means that I only enjoyed reading 7% of the whole manga and that's way too low for me to recommend this to anyone.