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.
YMMV: The Guided Fate Paradox
Alas, Poor Villain: Varael, Frunetti, and Satanael's deaths were given this treatment by Renya.
Ensemble Darkhorse: Liliel can be considered this, since she, just like Metallia, managed to rank in the top 50 fan-favourite (female) characters poll even though the game she's in hasn't even come out.
Player Punch: In the final lesson, Mysiel shows the difference Renya made in guiding his believer's fates. Almost every single one of his believers are now living happier lives thanks to Renya's guidance. However, once the vision ends, the Fate Revolution Circuit deletes his memories of said believers...
Tear Jerker: Rakiel reacts to the death of Renya with his usual poise and stoicism. Or at least he tries...his voice quivers REALLY badly at one point as he's scolding Kuroiel. Especially poignant: basically, he and Kuroiel are the ONLY TWO ANGELS who actually give a damn that Renya is gone (Liliel notwithstanding).
That One Boss: All the characters keep talking about how powerful Satanael is and how Renya has to really be prepared to take him on, and they aren't kidding. First of all, the stage constantly spawns mooks and even when they aren't hitting hard, they're still annoying you with their numbers and long range attacks. Then there's Satanael himself who has a lot of range and damage on his Beam Spam attack and has a tendency to teleport when you get too close so it's hard to even get a hit on him. Finally, there's his Kamehame Hadokenattack. The attack is marked with yellow panels and activates in a set number of turns, but depending on where you are when the attack is set and the placement of the mooks, you might have no choice but to take the damage and when you do, it hurts (at least 1000-2000 damage)! The best way to deal with him is to pump up your defense, plan your moves, and hope you can outlast him.