Ender Magnolia Boss Tier-list (Logic below)
Within this tier-list contains every boss, miniboss, and even a separation between the Arena Tower as a whole, and the individual members. It is entirely possibly I specifically missed one miniboss, but I doubt it. If I am wrong however, feel free to mention and I will try and specify where it'd go based on the logic. Speaking on the logic, here is what each tier means, and after that some explanations regarding what I predict may be topical bosses. Placements within the tier are also more or less ordered.
SS: Best boss in the entire game. Best combination of fun, memorability, and difficulty in a singular boss. Complaints on this boss would only consist of what would make it even better, and not things that currently make it worse.
S: Incredibly designed bosses with minimal issues in them. The rewards of these fights are some of the most game defining in my opinion where applicable. And generally these fights contain some of first things that come to mind if you were to ask me the most memorable moments in the game.
A: Great fights, great rewards, or greatly memorable moments but not necessarily all put together, or put together in lesser degrees comparative to S-tier bosses. They may also contain a few problems that without would make an S-tier boss.
B: Fights which are perfectly fine. Fun enough to where I would want to refight them, and memorable enough to where if I never did, I would not forget the general feel of the fight. Some may have also suffered purely by proxy of other fights, or got pushed up by nature of what they unlocked or being connected to memorable characterization.
C: Forgettable and/or boring fights, that while not bad are entirely overshadowed by other moments in one way or another with the unlocks or interesting moments they may lead towards feeling near entirely removed from the actual prior battles themselves.
D: Fights where the negatives outweigh the positives. Them either actively making me mad, or being annoying to fight. Most however, I would understand another person enjoying and are only personally irritating.
Absolute Gilroy (B): Likely one of the only unpopular opinions on this list, but I did entirely enjoy him as the final fight, even if I did expect worse in the Land or Origin prior to this alternative fight. As said prior, the only thing "negative" I can really say towards the fight is that I would've liked him to have a second health bar instead of four phases in one health bar. Perhaps having him use a heal much like your own to act as the health bar change, that would've been cool. But besides that, no complaints. Not even the downwards slam dealing a large amount of damage, it is very well telegraphed.
Yolvan: The first real boss fight of the game, and it is an incredibly unique one. Every attack feels unique to him at first and also introduces the greater focus on both your own, and the bosses mobility. This is not to say most of the bosses were slow in Lilies, but they themselves are faster in this game. On top of this, the sinking dread you feel as he drops to the ground when you deplete his health bar. You just know what's coming next, and I say Caladrius does indeed deliver. Finally, he is one of the most impactful unlocks. Between the auto aiming gunfire, high range saws, and poise munching drill, his generalist utility is without equal. All around a great nugget of game design.
Original Gilroy: You may ask, why is Gilroy's first version also so high. And the simple answer is that the vibe he gives at first is immaculate. The first major stepping stone you intended to reach, partially genocided by a brass knight. Only doubling as the "PTSD" of rain sets the mood in the first place. Said fears getting proven correct as the so claimed mutant speaks in perfectly clear sentences, and name calls the one and only Rain of Death. This is such a terrifying moment at first, that is just further sold by Gilroy being one of the first difficulty spikes in the game. Or I guess he is more so a complexity spike, but still. All around one of the most memorable moments in the game with a great first impression fight to match.
Shackled Beast: This one may be more so my biases towards the character than how actually memorable he is as a fight, but I can't deny just how much I really do enjoy the ol Shackled Beast. This manic, sane-insanity that is his personality before the fight starts is quite gripping as a character which just gets funnier after you do beat and add him to your team. But more importantly, beating this boss unlocks The Parry. Aka, my favorite move from Ender Lilies. I of course mean the Headless Defender, and not the standard parry. Only this version is even better since it doesn't have a limited number of uses and instead just a cooldown. That alone really is carrying this so incredibly hard, but I also enjoy the character to the point where it all becomes memorable by proxy.
Absolute Gilroy (A): This version of Gilroy, while sharing some of the same moves as his B-side, he unfortunately suffers from being a stepping stone to the better version. As such, he is much less memorable and is also just an easier fight in comparison. Less interesting overall, and lacks the grandeur of finality possessed by B. These factors combined reduce him to a mid ranking in A tier. Still a fun fight, but suffers too much from being "Daniel" to be ranked any higher than he already is.
Dying Reibolg: Likely the most batshit insane ranking I have on this tier list to most people. Namely, him being so astronomically higher than the actual Reibolg fight. However, I stand by this. The actual Reibolg fight is fairly forgettable, despite its status as a proper boss. The fear given by The Land of Origin, and the slog to get to Reibolg's fight in of itself detract from the moment, despite the implications. In contrast, when you expect an even harder fight from a blight enhanced Reibolg from the depths of the LoO, you instead face this crippled, dying, knight. It gives such a terribly sad vibe to itself that I just cannot really forget about. It is such a gripping moment of a fake out, to the point I decided to actively try and give what felt like a "Cool" death to him, while slow walking towards him. All in all, great scene setting even if the fight itself was practically a playable cutscene, and the unlock was too late for me, and most others, to really enjoy.
Luiseach: Under normal circumstances, the quality of this boss fight's design would've lent itself likely to the A-tier, even if the moment wasn't incredibly notable to me beyond the quality. The more interesting lore revelations happened elsewhere in the area. However, she did of course have that little pesky heal-bot. That little bitch was rather annoying. As such, it unfortunately causes the witch herself to get dropped a tier. She certainly isn't forgettable however, so B-tier is where she shall remain.
Armed Gilroy: The most fraudulent version of Gilroy. Suffering from multiple unfortunate fates, but most notably is the fact he is placed right at the start of the Gilroy Gauntlet, and also right after the lore revelations of the Agressor result in little means of interest. Only furthered by Gilroy seeming so out of place at the "Biological Research Facility". Although that technically is an incorrect assumption based on future lore developments, but it was my first impression. All this combined, and how easy the fight itself was, overall result in a rather forgettable fight that is carried by the quality of the reward, and being Gilroy thus not truly forgettable. But I couldn't name an attack unique to him.
(I don't really think any of the C tier bosses are worth mentioning why I find forgettable, with the exception of Reibolg, who was already explained.)
The Arena Tower: While each fight, excluding Mr. Oni, is fine or even great in a vacuum. Back to back they are just a tad annoying to play through. Forcing me to go through undeniably less interesting bosses so I can fight the best part again. This is only expedited by how annoying I further find the very first fight and his slash tornado. And while I do understand this is supposed to foreshadow how No. 7 fights, with each having part of the move set, that alone doesn't help it get out of D-tier. Perhaps this one is just a skill issue however, and if I were to do Luiseach first, and then the Arena Tower, I would've found it easier.
Velgrynd: Fuck you Velgrynd. Get your telegraphs outside the wall. Why is your hardest hitting move one of the fastest to come out? Why do you exist, kill yo- Anyways, The only boss I can truly say I feel is poorly designed with next to no redeeming qualities. I have zero interest in having to refight this bastard in the boss rush, but I do not really have a choice in the matter. If you like this boss, I question your tastes immensely.
These are, of course, just my opinions. And if I didn't cover the boss you are curious about my placement of, feel free to ask about it.