Berdly concept art:

In the overworld, he’s pretty much the same as Dr!Berdly, except for the fact that he wears fake glasses to make himself look smarter. In the darkworld, due to the enemies being 10x harder, Berdly’s forced (Kris forces him) to join Noelle and Kris on their journey through the cyberworld. Like Noelle, he’s apathetic, distant towards anything and everything, and doesn’t remember anything about his life, having to be reminded of who he is through challenging him at puzzles and his intelligence. His outfit is similar to Kris’s, which is the fact that he can’t take any of it (his armour) off without injuring himself (it’s up to you to interpret what that means).

Neutral route: his arm isn’t broken since he’s never controlled by queen (kind of, during the queen boss battle, she just forcefully brings him to her side), but he does forget some details of his life when he forcefully breaks from the fountain's control, rather than naturally recollecting his memories. In the library, he’ll get up and rub his head, asking why he was in the library, with Noelle having to remind him that he was studying with her.

If Kris took the pacifist route, during his time with Kris, he has to be reminded of who he is through challenging him (ex. Proving him wrong at puzzles, reminding him that he isn’t as strong as he thinks he is during battles; telling him it’s okay to not be smart, etc). He’s defensive of Noelle and (sometimes) Kris, if any of them were/are hurt (mostly Noelle), he gets more aggressive. The scene with Noelle and Susie is mostly the same, with the fact that Berdly never falls in love with Susie; he instead just apologises for how he’s been acting. During the final boss battle, Berdly comes in with assistance from Spamton, forming S.I.G.M.A! (short for Spamton’s inorganic gigas mech apparatus; punctuation included).

snowgrave/weird route: Berdly’s the main reason why snowgrave/the weird route in this au is possible since he gets aggressive whenever Noelle and/or Kris are injured/down. When entering a battle, you/Kris would have to act by either screaming out in terror, or by forcefully pushing Noelle to the ground (which is the more effective solution). By the time the three get to the alleyway, Berdly, in one last attempt to help Noelle, breaks free from the fountain, which still results in him dying and Noelle forcefully breaking free from the fountain due to the trauma.