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.
Wrathia being a Rules Lawyer in order to get out of keeping her end of the deal.
Maggie as well. She was willing to kill Ava and Odin because the later refused to apologize to her for kidnapping her even though his actions saved her life. She's even angry when she discovers they survived the crash and then she tries to convince Gil into sending Ava and Odin to the authorities. In all fairness, she had no reason to believe Odin wasn't lying and had in fact kidnapped her (and she did wake up to another girl bound and gagged right next to her, which doesn't really help his case). Although it doesn't excuse her willingness to let Ava die with him.
^^^ actually it makes a lot of sense in hindsight (though doesn't make it better), Odin says "Now it's clear why you were always rejected, you're a real monster Maggie" after seeing her use Tul's branch-arms power for the first time... (which is not a normal thing for her to do, and she hasn't been able to do it her whole life so as far as she knows— she is a monster) and the fact that she's already had six failed relationships where she was rejected and that's on top of the fact that something ruined her friendship with Ava (which could have also been a rejection)... I think he just happened to strike a big nerve of hers and she got angry and lost it...
Ava's social anxiety on page 1129 followed by a 7-page freakout weaving through the crowd of TITAN followers that actually DOES appear to be watching her every move.
And the fact that when Ava was dead SHE WAS RELIEVED because she's wanted to be die for such along, long time just so she wouldn't have to live with the pain of "her mind" telling cruel things to her and isolating her from ever having friends or people who cared about her every single minute of every day of her life... that takes an immeasurable amount of strength to deal with that.
Gil. Watching your home planet be ravaged by Silent Scavengers and dying from horrific injuries will do that to you.
Oh, dear God Ava. Having a demon who has constantly tried to kill her and caused her to have zero friends, as well as hints of suicidal depression from Ava? It's a miracle she's even alive.
Before he became a demon, Tuls was a guard serving a Princess that he fell in love with. His side of the pact involves seeing her one final time and finally confessing his feelings. Even if that means he will be rejected. Being the demon of Maggie certainly adds to the woobie factor as well.