Spoiler
I don't really remember much because I dropped it, but her parents betrayed their Kingdom (like the whole humanity) and Arthur because they blackmailed them from the fact that Tessia's mana core is infected, the bitch being dumb urges Arthur to save both her parents (they are already dead btw when they got there) but got sylvie to sacrifice her self from it instead in order for Arthur to live because of they got caught up in the fight during it. (Its also Elijah's fault because hes a fucking antagonist) And now Arthur is not himself anymore, but only physically, his face change as well as his body, and his at the enemy base (for some kind of reason he got teleported to their base) Sylvie (not sure if shes dead) is nowehere to be found, and Arthur's mana core is broken so he cannot use his mana now, (although he suppose to be a white core) but he uses Aether force, and its much stronger than mana.
You just summarized the whole story of Arthur’s life Lol, but let’s be honest, most of the people hate Tess because she’s Stupid and I’m not gonna lie....... she is.... BUT(big but) she’s a teenager and if I was her I would’ve made more bad decisions that what she had made, (I’ve felt like a philosopher all day so let me be one) People have the tendency to compare other people to someone more successful than the other person is and I found myself doing exactly that comparing Arthur and Tess. Some people honestly sometimes expect a lot of someone for I don’t know what reason is but Arthur have a lot of advantage he learned from his previous life and Tess didn’t have any of that so we really can’t hate on her for that.
Wtf? I didn't expect that they would actually include the romance from the novel to the manhwa itself, now I'm disappointed because I knew whats going to happen when they put the romance. Damn it. I'm not a Tessia hater its just that it's her goddamn fault that everything became a mess from the novel. (Not gonna spoil)