That's Clockwork Mansion. Originally it was supposed to be the forum from the inverteddungeon.com website when its owner decided to have his site have its own forum rather than use icvdforums.com, but because of a number of furry influences (inverteddungeon.com hosting Mabsland and the Adventures of Dan & Mab, a furry comic, plus a number of personal influences on the inverteddungeon.com owner/host), that forum became overrun with furry aficionados, to the point at which the core "Castlevania" (and CVRPG Comic) audience became minimized, then they outright left. I doubt that there are any Castlevania-only fans posting in that forum.
Icvdforums.com/forums (ICVD) is not affiliated with inverteddungeon.com any longer, it is its own forum, with many of the members being what would be called her a "Master Hunter" (an oldbie dungeonite, a senior member). They've been around since the days of the threaded old Castlevania Dungeon Forums of 1997+, like I have.