The Frontier is a mod for Fallout: New Vegas released earlier this month after years of work. With a playable area the size of the base game's Mojave Desert, three faction storylines, and driveable vehicles, it was hotly anticipated—so much that when it was released it drew enough visitors to crash the NexusMods website.
You won't find The Frontier on NexusMods right now, however. It's been removed by the modding team, and replaced with the following statement:
"Some deeply concerning news has emerged in the past few hours. We have been recently notified that one of our developers, ZuTheSkunk, had posted animated pedophillic content on their personal artist accounts. The items in question are deeply disturbing to the entire team, and we condemn them in the strongest sense. ZuTheSkunk has since been removed from the Development Team and banned off of our Community Discord. We will be conducting dialogue with members of the development team to hear their thoughts regarding the current situation and help make our decision more informed. We have stopped production and work on the mod to address the current events properly. More measures will be undertaken and a more detailed address will be posted soon."
Players have previously raised concerns over some of The Frontier's content, and the way it's written—in particular, a teenage girl who can be made into the player-character's sex slave, and a settlement of reptile-people who have sex with humans. While the Fallout games have dealt with adult themes and let players behave in morally reprehensible ways—and not shied away from slavery in particular—even players impressed by the mod's technical achievements have been critical of its "fetishized characters".
The Frontier also has a Steam page, but has yet to be made available there. If you're looking for some alternatives, consider one of these New Vegas mods instead.
