Tenna's getting Possessed in Chaper 5

For this theory make sense, we have to accept Mettaton either is the Knight, or is in the Knight Groupchat.
If you can't jive with that, give this theory a miss.

TENNA'S ART STYLE IS WEIRD

One strange thing about Tenna is that he goes against an unspoken style rule.
Generally in UT/DR, the closer to ‘real life' art style something is, the more unsettling and out of place it is implied to be.
The Titan has rotoscoped human proportions in some scenes, Photoshop Flowey is an asset collage, Jevil’s battle uses a photo background.

Tenna, though? He is 3D where no other character is. Many of his slides and backgrounds are asset collages. He actually shares a TV asset with Photoshop Flowey.

Why would Tenna be the one exception to this rule?

Unless… he isn’t, and we’re going to see him in a more unsettling context later?

ABOUT "METTATON"

"When I was coming up with the concept for Tenna, the first thing that came in my mind was that I wanted the players to think that the character looks like Mettaton."

Toby Fox, fan translation Issue 9/25, UNDERTALE 10th anniversary.

I have been wondering about this quote for a while now.
It makes sense to remind the audience of Mettaton a little, because he's clearly going to get a subplot with Tenna, but to make that reference your first priority? Seems excessive, doesn't it?

I've gone over how meta this plotpoint is in my other writeup, but it does seem to confirm you are expected to play Undertale before you played Deltarune.

We know Tenna has been around from the start of development.

"By the way, the music played in the "TV World" area was started to be created around 2015-2016. This is one of the the[sic] earliest songs I wrote for "DELTARUNE", and since I wrote it right after "UNDERTALE", it's very Mettaton-esque...
I have many other stories to share, but I don't think there's much space, so I'll stop here!"

Toby Fox, [same interview]

Toby adds more explanation on Twitter later.

About "Tenna." I invented this character a long time ago. In 2016 I cought a Kinect in order to rotoscope his movements, but I quickly abandoned this idea.
I also wanted him to do MMD dances (I also abandoned this idea). Anyway, this is why I was "learning 3D" at the time.
For many years I wanted him to be rendered in a "Ghost Trick" style of lineless 3D. However, this looked tremendously bad, so I slowly abandoned this idea.

Toby Fox, Twitter, Jun 19 2025

("MMD dances" refers to MikuMikuDance, a Vocaloid software. Mostly used for music videos. Another odd Mettaton-y detail.)

Finally, Toby reiterates this in the Winter 2025 Newsletter, saying part of the concept was:

"Let's have a TV character who will be like Mettaton!"

He also adds:

"I composed the music for "TV World" in 2015. I used the project file for Mettaton's battle theme as a base. Closer to release, I modified it to add the theme from Hip Shop / Green Room."

"I drew Tenna in 2017. Before that point his name was "Mr. TV Guy."

In another tweet, Toby said he is pleased people don't see Tenna as a budget Spamton.

Before the game came out, I thought people wouldn't really care about Tenna and simply dismiss him as a budget Spamton. I'm glad everyone seems to like him just fine. I see those two as intentionally similar characters who mutually enhance each other. You know, like Spy vs. Spy.

Toby Fox, Twitter, 17 Jun 2025

Spamton was likely invented to fill a hole in the NEO fight, which we know previously did not include Spamton.

"After creating UNDERTALE, one of my goals for DELTARUNE was for players to finally be able to challenge a "real" version of Mettaton NEO that didn't just end in one turn. For that purpose, I actually created a few music mockups for an extended version of Power of NEO.
There's even another one from 2016 (lol)
...Eventually, the boss concept evolved to involve Spamton, and with that, the music changed as well.

Toby Fox, [Rejected Chapter 2 Tracks, Fangamer.](https://toby.fangamer.com/interviews/chapter2_music/

So Toby probably made Spamton out of what he had already created for Tenna, as a quick way of giving him some substance.
Spamton's only known concept art is of the earlier Mad Mailer.
Toby notes in the concept art dump:

These ideas precede Virovirokun, Spamton, and Maus.
Seems like Mad Mailer's tie would have been prehensile.

The Dilbert tie is a trait of Tenna's, so it does seem the Mad Mailer concept was also based on Tenna.

But Toby conspicuously does not mention Mettaton in that tweet, even though that comparison would be far more obvious- probably because being a budget Mettaton is the intended viewing of Tenna's character.

So: Tenna is one of the earliest characters made for Deltarune, despite lacking a real name for years.
The point of Tenna is that he is a knockoff Mettaton. Deltarune Mettaton hasn't done anything yet.
Giving Tenna to Mettaton implies you are familiar with Mettaton’s storyline of wanting a robot body from the original game.

What does this add up to, exactly?

TENNA'S ROLE IN THE PLOT

Where is Tenna, as of chapter 5?

There's 3 ways things can go for him. Mettaton gets Tenna, Tenna is in Castle town, or Tenna goes missing.

But Tenna is an active liability to keep around in Castle Town, because he knows Kris is in league with the Knight. He almost let the truth slip already in the Sword route games. The other characters who knew too much, Ramb and the CH3 Bibliox (The Hymn book on the table is gone), have conveniently disappeared, likely spirited away by the Knight or some other shadowy figure like the mantle boss or FRIEND.

So it is in everyone’s (except Tenna's) best interest if… something… happened to Tenna.

PROPHECY

Tenna getting attacked was foretold by the prophecy.

One thing that is interesting about Tenna’s prophecy panel is that it is purple, when most of the others are blue.
The second sanctuary panels are purple, including THE CAGE/THE PRINCE, the GIRL ones, and GALLERY.
(Gallery.ogg plays before fighting King, Queen and the Titan- but not Tenna, which might indicate we haven't had the REAL fight with him yet.)

The prophecies are Susie purple, and Susie represents defiance of fate.
I think the purple suggests those panels either can be changed, or are actively being changed.
A few possibilities:

• Susie’s intervention is changing Tenna’s fate, finding his employees to fix him saved him. So Tenna is not actually supposed to be alive, meaning he is still in danger.
• ’LORD OF SCREENS’ is an interchangeable title, like the ‘GIRL’.
• The Knight deliberately failed to kill Tenna, because Knight Groupchat has an alternate use for him first.

WE'RE GOING TO GET ON...FAMOUSLY.

Tenna has a ton in common with Mettaton, at least in their physicality and design.

• Big male robot
• White gloves, that were 3 fingered in the concept art
• Gigi's concept art having what I can only describe as TV anime hair.
• Catlike canines
• Same suit
• Generic Tumblr sexyman body, especially compared with the antlike body on Tenna's earlier concept art
• White face
• Caps lock voice
• Star/showbiz motif
• His 8bit form is hot pink like Mettaton EX
• A hidden face on his torso, same as Mettaton EX and Mad Dummy
• Tendency to repeat things three times
• Loses both his arms
• Constantly dancing
• And a few shared poses. In particular, Tenna's pose where he holds his head with both hands is straight out of box Mettaton's pose set.

Remember, Tenna was created and designed after Mettaton.

I think there's a deeper point to all these similarities, and it's this:
If Mettaton possessed Tenna and pretended to be him, no one would notice the difference.

How would Ralsei or Susie be able to know? As a player of Undertale, (you) are the only one who might be able to notice if such a swap happened. It would be supremely meta, which I think Toby likes.

Mettaton is an actor, so he'd be capable of at least a passable job at this.
This plan would benefit #teamroaring hugely. As ‘Tenna’, Mettaton would be trusted implicitly by the fun gang and everyone in Castle Town. He could run interference, go anywhere, and create any needed distraction.
Tenna desperately wants to feel needed, so he'd go along with the plan, especially if Kris was in on it.
Susie likes Tenna, so there's even a built-in hostage if things go sideways.

Thematically it would make sense for this to be Tenna's fate, a big running motif in the game is puppets and vessels.

Tenna’s a matched set with his old business partner Spamton, who became a puppet. Tenna is arguably the Groupchat’s puppet already, obeying Kris’s orders to keep the Fun Gang busy.

WHO DOES THIS SMILE BELONG TO?

Did you say Tenna? I'm pretty sure you are wrong. This expression has never actually been seen on Tenna when he's a Darkner.
(Which is quite ironic, considering for fan Tenna designs, fandom had nothing to go on BUT that smile...)

Tenna's face goes black or static when he's being ominous, but it does not smile.

This smile has been seen only on TV sets around TV World, and on Tenna when he's a televison.

For example, on these TVs following Kris around.

The TVs still smile at you when Tenna is having a breakdown, so he doesn't really have time to be smirking ominously. Which adds further doubt that it is his smile.

This smile seems deliberately generic. The closest resemblance to any existing assets it has to is Sans's mouth sprite.
Who is this? Is this FRIEND, the Knight, Mike? Mettaton? Battat's Mike outfit has a smile just like it, so it could be Mike.
The text would certainly point to it being the Knight....

Anyway, I think it will be very bad news for us when this face actually appears on Tenna the Darkner.

COULD IT BE IN CHAPTER 5?

We know the next Dark world will probably be Asgore's house.
The (non canon, but still written by Toby) Fangamer ad for the hero figurines has Tenna electrically travel through a wire to transform a regular TV. Asgore's house just happens to have a TV set with similar antenna to Tenna.

Tenna only created TV World because he was plugged in and his ‘light’ changed things- we actually don’t know what would happen to an unplugged TV or computer if a Dark World was made.
Queen, a laptop, became a living Darkner, but the desktop computers became terrain. So the logic for what gets to be alive in a Dark World isn't necessarily consistent, they are dream worlds after all.

That might be overexplaining it, though. ‘Tenna’ can just make up some excuse why he would be in that Dark World, Susie would be happy enough to see him that she wouldn't think twice about it. Ralsei travels between Dark Worlds independently and no one has asked him how he does it yet.

CH5 TRANSLATION TEXT

Toby posted some sample translation text from CH5 on Twitter.

This text is in parentheses, so it’s probably narration.
I would imagine it’s intended to be a callback to Asgore calling flowers ‘good listeners’, so it might have to do with the Flower King TV. It has a condition listed: ‘only if you had [Cuts off here]’.
This could be a previous choice made, so it might relate to what your playthrough did with Tenna.

Perhaps Kris has recently been talked at by a motormouth Tenna, who did not listen to them?

TENNA_ALT_PLOT

The script function for if Tenna is broken and can’t be repaired is called tenna_alt_plot.
In this scenario his corpse is never found, so it’s likely the Knight took him away.

Letting this narrative happen, where he breaks and no one cares, confirms Tenna’s feeling of being a broken toy no one wanted. My guess is if you let him die, it will embitter him in some way that makes him impossible to reason with… which would be relevant, if you fight him again.

I felt like you.
I felt like a broken toy nobody wanted.

Susie to Tenna, CH3

CH5 NEWSLETTER SPRITE

One sprite in CH3 is interesting- Tenna's smash cut. This face is unusual, because it goes off model.
It’s the only one that gives Tenna a black mouth cavity, when it’s usually purple. I think it’s meant to resemble Spamton’s sliding puppet mouth.
The 2025 Winter newsletter gives us a seasonal variation.

Aside from the holiday additions, this is a face we haven’t seen before. It has fangs, or perhaps broken teeth.
I don't think Tenna's face would be made scarier for a Christmas image, so this is potentially a cut variant, or something from a future chapter.
Even if Tenna has no relevance post CH3, it’s not unlikely we would fight him again, as there is a dojo in Castle Town.

But in a friendly dojo fight, why would he look more like a breaking or scary puppet?

CH5 CASTLETOWN SCENE

In the Winter 2025 Newsletter, a scene is released of Tenna talking to Battat in Castle Town.
So either Tenna is already Mettaton, or leaving Tenna in Castle Town will save him from this fate.

In that scenario, the plotline doesn’t happen at all, or Mettaton swipes another vessel instead.
If the plotline happens with a different character, I think the most likely fallback would be Giga-Queen, as it’s a robot body that exists in all playthroughs.

There’s something odd about the Castle Town interaction.
Tenna ends by giving Kris what can be interpreted as a direct order, for no apparent reason.

Tenna’s relationship with Kris is not exactly one of equals, so would he casually boss them around like that? (Although, could Tenna be bossing (You) around on Kris’s behalf like CH3...?)

I think there is something up with him. At least, Kris has been talking to him behind our backs again.

I DON'T MISS TENNA

And on a closing note, a last TobyTweet, this infamous one about Chapter 5.

Toby's friend is probably a completely normal person who doesn't babble in fan theory doublespeak, so the logical reading of this is simply 'I have seen way too much of Tenna' or ‘Tenna is being a pain in the ass’.
So either Tenna's dojo fight is pure pain, or...?
Well, 'Tenna' definitely would piss you off, if he's a puppet of the Knight...

My Other Deltarune theories
Mettaton is the Knight
Rosegrave, Or Who Made Weird Route?
Dess is the Earth