They are fine with the game being modded what mostly bothers him I think at this point is having the mod hosted on the official forums and the potential for his writing to be mistaken for some of the lower quality (although still appreciated by me) material of the mod. If Kitteh were hosting the mod on his own site then yeah it's an open source project so everything is fair game. But right now the Mod is being hosted on Fen's Forum on his dime so contents are subject to Fen's approval and those of his appointed forum moderators such as Savin. If you ever want hellspawn content you are gonna need to find a new home to host the mod. And even then at this point it would still probably be a bit in bad taste to go against the original content creator's wishes. But yeah as long as you are in Fen's house you gotta play by his and his team's rules.
One, there are a few places where we accept all changes within the mod as being ours, Kitteh and crew, and disavow any involvement of Fenoxo and staff except where explicitly stated, including the credits page within the game.
This is not the home of this mod, Trello and our wiki take that right. This is a welcome bit of publicity we thank Fenoxo for.
I have yet seen a game that has been released as a mod game by the company or individuals who own it whom say this game is moddable except for this part or these characters.
If Savin is so dead set against it being altered, he should have removed all his work from the game before Fenoxo made the source available.
Kitteh, being the creator and coder of this mod, has stated that all of Savin's work is verboten when it comes to making modifications. We, the mods crew, respect Kitteh, thus his decision will be abided by Revamps crew.