1st episode was, essentially a prologue, so that we can learn some generic bits about the local interpretation of Final Fantasy's Garlemald and fuel the revenge theme (which was obvious from the very first moments, considering how much Adonis was sulking and showing off his frustration). This is not bad, but it is very difficult now to predict how it will go from this.
It can become a story only about killing everyone for the sake of the aforementioned revenge. That would probably be boring and not worth even 12 episodes. Or it can be that, but with "a girl's love calms the revenger down" kind of thing. Kind of like 2001's "The Believer" with Ryan Gosling.
But... Most likely it will turn out that... Witches were never any different, and that that this "Gear expansion" is actually based on the magic, that those "witches" were using. Why? Because it is clear that a human was able to learn magic, and considering that even at that point this world has existed for a very long time, I am pretty sure he was not the first one.
So, it will start as revenge story, but at some point it will shift into something like "people need to know the truth, and for that to happen I can't kill all of them". Which is also fine, but it may be difficult to sell considering the 1st episode. But if they will succeed - it may mean, that the story is relatively good.
Also, what was really the point of summoning that big sword in the desert after the fight was over? Flaunting it like that only proved Chloe's statement that Adonis is inexperienced with magic.