To add on, the beast seems to be in genuine pain and outright avoids Flumpty when making to the office.

After killing twenty people in his twisted game, he stitched their bodies into the Eyesaur, which is still alive and conscious.

On top of that, only Birthday Boy Blam and Golden Flumpty seem to be actively enjoying the game, so it's likely that he forcing his gang into doing this.

After they die, he cooks their eyeballs and skins their bodies.

In search of a best friend, he had started a hide and seek game that involves him and his gang brutually murdering them when they find them.

Randomly enough, he had forced a man into drinking lava, causing him to become the Redman.

Furthermore, he did this so as to killing approximintly 100 billion birds with a meteor, adding animal cruelty to his list of sins.

He had caused the literal Apocalypse in New Dork City, while it was mostly offscreen villainy for a while, we actually get to see the town in flames in the bad ending of ONaF 3.

One of the 'corpses' shown in the ONaF 2 office implies at least some of them are still alive, which means Flumpty also tortures them.

At some point in time, he had brutally killed several fictional characters (replaced by Jonochrome's OCs in the Fanverse remasters) to have as decorations in his funhouse.

He broke into a guy's house because he was cooking eggs, and was voluntarily arrested just so he could break out of prison.

He once gave a speech about the importance of life, and then killed a guy for no reason.

For the longest time, Flumpty had wreaked havoc on New Dork City just for his own amusement.

As mentioned before though, none of that is confirmed, and it is more likely that he just stopped being evil instead of actually redeeming. It is unknown what this means, but some have interpret it as Flumpty ending his twisted games on the residents of New Dork.

At the end of One Night at Flumpty's 3, an image of Flumpty ascending to a white light appears after the Good Ending.

However, he has been shown mistreating him several times, such as threathening him to tell him what his birthday is and even killing him in ONaF 3, making this unlikely.

It's possible he still has some care for Birthday Boy Blam, as he is usually seen with him and had helped satiate his appetite after he realized he was hungry.

Visit here for more details: Flumpty's Synopsis on the Villains Wiki.

2.3 What Prevents Him From Being Pure Evil?.

2.2 What Makes Him Close to Being Pure Evil?.

One night at flumptys 2 wiki