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: Keys to the Kingdom
Complete Monster: The antagonists are largely cursed, have sympathetic reasons or both, but Superior Saturday is an out-and-out monster. Her method of disciplining subordinates is to turn them inside out and turn their blood into glass, essentially making them an organ jar. Since her subordinates are immortal, this is a Fate Worse than Death for however long it's in effect. She's practically the Big Bad herself, being behind most schemes since the beginning of the series, including releasing a mind control virus, attempting to nuke a town, throwing a man into Nothing to be dissolved and blaming his brother, and more. What do all of her schemes focus on, you ask? She wants to be the woman in charge. She wants the Incomparable Gardens. She should have been favored during the creation of the Universe, not Sunday. That's it. It speaks volumes that her supervisor kills her and no one views it as his own Moral Event Horizon moment—especially because said supervisor is the man she tossed into oblivion.
Crowning Music of Awesome: Arthurs's song in Grim Tuesday, which won him the Second Key. And it was just a song he made on a xylophone when he was a kid.
I Knew It: Let's face it, the Will turning into the Architect when it was completed was just obvious.
Informed Villain: For someone whose sin is Pride, Lord Sunday's sole shown (rather than exposited) motivation is to be left alone and for the universe to continue existing. Despite the fact that his key's primary power is to override the other keys, he leaves the heroes alone and doesn't ever step in to hold him down until Arthur is on the verge of destroying the entire universe. His section of the house is well-maintained with happy, productive residents and he refrains from doing any more than harming Arthur and bluffing him a bit when he needs to obtain the keys, even though most people would probably stoop to a bit of harm solely for spite's sake.
Neutral Evil: Lord Sunday. He doesn't have any grand scheme, any ambition, all he wants is to be left alone in his Gardens, despite the severe repurcussions to the rest of reality.
What Do You Mean, It's Not Symbolic?: Everywhere. The series itself is named for a line from the gospels, and it just gets deeper from there. The Incomparable Gardens are a fairly obvious reference to the Garden of Eden for a start, and given that Lord Sunday's sin is Pride, he could be interpreted as the equivalent to Lucifer. Saturday's Tower, built with the intent of reaching the Gardens, calls to mind the Tower of Babel. The Incomparable Gardens are also hosted on "Drasils", which is suspiciously similiar to the word "Yggdrasil", the World Tree of Norse mythology.