Castlevania: The Bloodletting
Every game series has a number of oddities that come along over time. Some games shift and change as certain bits that work (or don't) are added and removed as the game is developed. Sometimes this results in a game being canceled (see Castlevania Resurrection), while other times, such as in the case of Castlevania: The Bloodletting, the announced game becomes some other game entirely.
Early reports indicate that Bloodletting was originally conceived as a follow-up to Castlevania Dracula X: The Rondo of Blood. The heroes of the adventure would have, once again, been Richter Belmont and Maria Renard, who had to team up to take on Dracula once again. Along the way there would have also been a rival, another vampire hunter looking to make a name for himself (and possibly battle with Richter) who would have acted as their adversary and confront them at multiple turns of the plot.
Richter, Maria, and the Rival are shown on this page, with their concept sprites being the only existing art of this proposed game. It's interesting as the Rival (the man in red) more closely resembles Richter -- he's essentially a re-skin/recolor of Richter's original sprites. Richter, meanwhile, gained a complete redesign, making him look drastically different (and not at all Richter-like) -- this would lead to the eventual redesign of the character in his later appearances in the series, of course.
Whatever Konami's plans were for this game, history was not on the side of the game: it was planned for release on the 32X add-on for the Sega Genesis, and that add-on was an utter failure at market (one of many add-ons and adapters Sega released in quick succession right before putting out the Saturn, and none of these additions, Saturn included, caught the world on fire). With the failure of the the 32X, Konami reportedly canceled the game and shifted the team to other projects. Eventual series lead, Koji Igarashi, was part of this team and, after work was stopped on Bloodletting, Igarashi took the elements he could from this failed title and salvaged them for his next adventure: Castlevania: Symphony of the Night.
It's worth noting that although some attribute the name The Bloodletting to fan invention, Konami did register a trademark for that name in 1995. They even advertised it at the 1995 Chicago Consumer Electronic Show (the name, anyway), before quietly canceling it. While the game did die it's cancellation did lead to the eventual creation of Symphony of the Night, considered by many to be the finest game in the series. If we had to lose one game to receive a masterpiece like that, maybe it was worth it in the end.
Legacy of The Bloodletting:
As we know, Richter would appear in a proper follow up to Rondo of Blood, the beloved Symphony of the Night. Some of the artwork from Bloodletting was even reused, with Fake Trevor (of the Zombie Trio) using recolored Richter sprites. Meanwhile, it's possible some of the ideas for the Rival could have gone on to influence Richter (and his plot elements) in the sequel (although that's just fan speculation at this point).
Meanwhile, the Rival has gone on to star in a Castlevania game, albeit a home-brew fan game. Appropriately titled Castlevania: The Bloodletting, the game is a faithful entry in the series, one that shows a level of polish many fan-brews and hacks lack. We recommend, if you're going to grab it, get it from a trusted source -- we nabbed our copy from over at Pixel Prospector (and we are in no way affiliated with that site, nor do we have any reason to advertise it other than they have a decent copy of the game).
Of course, we'd be remiss if we didn't also mention that the Rival continues to live on at The Inverted Dungeon and her sister site, the web-comic CVRPG. On our sites we've renamed the Rival as Hanz Belmont, brother of Richter Belmont. We have his bio posted once again, but you can also check out Hanz's adventures with his brother in CVRPG's sorta-spinoff, DSWC.