How do you PERSONALLY define Bonus/Secret Bosses?

With the addition of new chapters, our previous definitions have all likely changed, so I'm genuinely interested to see how you guys define them.

Here's how I personally define a Secret Boss.

  • You can progress the game without needing to encounter or defeat them.
  • While not relevant to the Chapter's plot, they are relevant to the game's/chapter's lore to some extent.
  • You have to go out of your way to battle them.
  • They're significantly more difficult than other enemies.

By my definition, Jevil, Spamton, Eram, Mike and Hammer of Justice are all secret bosses. Hammer of Justice is debatable, but the fight itself, isn't exactly too relevant to the plot, while still having some lore implications. This does exclude the Knight though, as they are by no means secret, and their fight is indeed plot relevant. This is why I prefer the term Bonus Boss, as immediately, it's chalked up to one requirement.

  • Defeating them is not required to progress the story.

While not secret, I can definitely make a case for the Knight being a bonus. Sure, you're forced to fight them, but you're NOT forced to win. Victory's just a bonus. All the other secret bosses also fall under this definition too.

Of course, this is my PERSONAL definition. Very interested in hearing anyone else's! (I will emphasize this again. These are your PERSONAL definitions.)

I'm not awfully pedantic about categorization since Toby broke the formula of "every chapter has 1 secret boss that has a shadow crystal". However, if I had to, I would probably separate "optional boss" and "shadow crystal boss". There is ERAM who is part of a shadow crystal boss quest and has the difficulty level to match a shadow crystal boss, but still falls under the same category as Mike, and I don't neccesarily have a problem with that.

I prefer the term Shadow Crystal Boss, as it only includes bosses that CARRY shadow crystals. You can use whatever term for the rest. "Secret" disincludes the Knight, but nothing else. What the term "Bonus" disincludes depends on your definition. But "Shadow Crystal Boss" refers to what were previously called secret bosses, but still includes the Knight.

I call them secret bosses cause i’m used to that
I include every shadow crystal boss because YES THE ROARING KNIGHT IS A SECRET BOSS !?@& YOU- and I include Mantie as an honorary member cause like come on

There's a difference between a boss that is secret and a Deltarune Secret Boss. Bosses that are secret are people like the Mikes and Mad Mew Mew in Undertale. Deltarune Secret Bosses are fights that are way harder than most other fights and give you a Shadow Crystal when you win.
The Knight is clearly intended to be the secret boss of Chapter 3, the quest is just much more disconnected from them than the others. Going by formula, ERAM is either a living equivalent of that one teacup part in Queen's Basement or the "Chapter Boss" of the Original Game.

The Roaring Knight is a mandatory final boss. It's not a secret by any definition of the word

Ah,but you see my friend inside me, it’s a secret that you can win.

Anyway yeah i count the mikes too cause i mean come on they have the freedom motif for nubert’s sake

A secret that you can win, but not a secret that the fight exists.

The latter is what's important to being a secret boss. Every secret boss requires you to go out of your way to start the fight. The Knight is no more of a secret boss than Tenna.

The mantle is the secret boss. The Knight is the Shadow Crystal Boss.

I consider all of them “secret bosses” as a blanket term

All 6 of the ones I count as secret bosses

Reminder that these are PERSONAL definitions. Not trying to establish something as official when it’s not. (And that it should be established the Shadow Mantle isn’t required to win)

It’s not in their battle theme, and Gerson is the Chapter 4 secret boss

Also, nobody talks about this, but the Airwaves filename is spamton_dance, so I think it was composed for something with Spamton and just ended up being used for the minigame

Secret bosses for DELTARUNE
Chapter 1: Jevil
Chapter 2: Spamton NEO
Chapter 3: Shadow Mantle Holder
Chapter 4: Hammer of Justice and the Mikes
It's clear that these are intended to be secret bosses, so they just need criterea to match that. I think that, if you are required to fight them to continue, they're not a secret boss. If they're easy to find, they're not secret, and if they're too easy and don't have a special theme (by that I mean a battle soundtrack different from basic enemy encounters), they're not a boss.
In general, I think "secret bosses" is a decently straightforward debate, unlike some other topics (cough Knight theories cough). There's clearly a difference between shadow crystal bosses and secret bosses, though.