Here's info on Baxter

Originally they would have him be part of the Hazbin crew/cast. But Sir Pentious was originally intended to be a one-off "villain-of-the-week" type character for the pilot only, but he grew on Vivziepop and the Hazbin Hotel fans so much that she decided to give him a bigger role in the series.

Thus he took Baxter's place as the inventor/mad scientist.

7929630
Man I fuckin hated Sir penthouse but now I can't see my boy Baxter in action.

Man I swear, we can't have anything nice.

7929630
Never trust the Hazbin wiki.

I'm going to be honest with you. I may not be the biggest Hazbin Hotel fan meaning I'm not going to know 'everything', but I would never have heard about this Baxter guy until today. I do not even remember if Baxter was ever mentioned during the pilot.

But I will say this. I thought Sir Pentious was just going to be those one-off characters. Yet while I find it too early to call him the next 'Arthur Fonzarelli' or something, I get why people are suddenly naming him a surprise favorite. I look at Pentious and I see him as a Doofensmirtz or something. Someone who's slightly evil and yet likeable just the same. I'm not expecting this guy to have too many tragic back stories, but hopefully we learn more of him as we intend to do with the major cast of this series.

7929630
That and i believe it was said one of the characters was going to be killed. SP fits the bill there. The others have to much riding on them.