Berdly Deltarune is the single most complicated Deltarune character.

To begin, we must state what SHOULD be obvious, but isn't always...

Berdly isn't romantically interested in Noelle. AT ALL.

Berdly isn't romantically interested in Noelle. He says this explicitly during one of the most emotionally charged scenes in the game (immediately after the Ferris Wheel) and people STILL manage to miss it. I've even seen people straight-up intentionally ignore this fact because it doesn't fit with their perception of Berdly.

Why is this important? Because it subverts the player's expectations of Berdly.

Up until that point he is built up as this nerdy loser incel who is a rude little bitch to everyone for no reason, yet this simple fact goes against ALL OF THAT.

Indeed! Every single time Berdly is shown being nice to or "interested" in Noelle is entirely recontextualized!!!

He's NOT being nice because he expects romance in return; he's being nice because he is a good friend.

Why does Berdly do this?

Berdly goes OUT OF HIS WAY to pretend that he has feelings for Noelle because he is convinced that she likes him. Why does he do this? Is he a self-absorbed narcissist?

NOPE! Berdly is no narcissist. He is a genuinely intelligent kid (you can't get consistent A+'s just from "pretending" to be smart) who has HORRIFIC imposter syndrome.

He has internalized the fact that he is just a "forgettable little bluebird" to the point where he can't understand that he actually has any positive qualities and instead assumes that he must be somehow "faking" it all and is terrified of being found out.

That's why he goes out of his way to be a jerk. He doesn't actually know what "smart" people should act like (spoiler alert: there is no answer) and instead of being himself he feels like he has to pretend to be superior to everyone all the time. If he ever lets his guard down, he is convinced that he will be found out.

Berdly can't get social cues.

This is self-explanatory. Berdly is, in my mind, extremely autistic-coded.

As a horrible combination with his imposter syndrome, Berdly cannot read other people very well at all. Since Noelle was, as far as we know, the first person to ever really treat Berdly like he WASN'T a forgettable waste of space, he is extremely protective of her while simultaneously being utterly incapable of understanding why she acts the way she does.

Berdly thinks Noelle is nice to him EXCLUSIVELY because she has a crush on him. He genuinely cannot process the fact that he deserves any level of positive attention and instead believes that she is acting irrationally because of romantic interest.

Berdly demonstrates this MULTIPLE TIMES!!!

The moment Susie is actually nice to him, he starts thinking of her as a potential romantic partner.

If you try to talk to Berdly after the Queen fight enough, he will even think that Kris is romantically interested in him!

Berdly ONLY shows romantic interest towards Noelle because he is UTTERLY CONVINCED that if he doesn't reciprocate her (nonexistent) feelings, then she will no longer have ANY reason to be his friend.

That's why Berdly acts like he does. He believes so wholeheartedly that he has no noteworthy qualities that he cannot understand why someone would be his friend unless they wanted something in return.

Summary:

Berdly's story is an incredibly sad and compelling story about an autistic-coded teenager—terrified of losing the only friend he's ever had—who is CONVINCED, despite all the evidence to the contrary, that he does not deserve the praise he is given.

Take THAT, Berdly haters!!!