These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Angst? What Angst?: Kole's backstory, where he was left behind by his camp because of his disability. This is lampshaded by Kole and Aida in the beginning of the third chapter.
Queen Kathleen counts. Being forced to give her daughter, Aida, up when she was young, being the only Noble capable of emotions, having to watch her son, Kael rule Valond despite his ruthlessness, being betrayed by Synius, who allowed Aida to be tortured and emotionally broken by King Kael, and finally being killed by Synius after he decided she knows about his manipulative ways. She even tells Synius that she had died long before he ever threatened to kill her.
Jace counts. He lost his parents, then lost all of his comrades in the Knight Order because of the Eagles, including his beloved partner, Cain, then learns Cain was Diego, The Leader of the Eagles in disguise, and is now attempting to build his own order of warriors.