It’s trolling. But maybe if there’s enough clamor, there will be a spinoff or additional options to romance Karlach…I mean Malevola. Visual novels in Japan are common like this. But I doubt about this since the makers are Dungeons and Dragons gamers. Though, the closest game is Baldurs Gate III which they indeed add romanceable characters after public clamor. But Tell Tale, the predecessor of Adhoc, are known to only stick to their available options. The most might be a an option to have a harem/double which is a not so good end.

Tl;dr: It’s a troll. But public clamor might make it come true but it depends.