In the mid 1990s polygon graphics became all the rage. Companies that had made names for themselves creating fantastic stories with detailed sprite-based graphics suddenly were chasing the dream of converting their series in the 3D graphics to reap mega-bucks. The thought that traditionally 2D games could somehow be converted into 3D was all caused by one game specifically: Super Mario 64. Make no mistake, Super Mario 64 was a gem, a massive acomplishment that managed to translate what worked about Mario in 2D into a 3D world while still being hugely fun.
The thing was, though, that not many games worked as well in 2D as they did in 3D. Series that made the move successfully, like the Mario titles and, later, the Metroid Prime sub-series understood what worked about the original games and what had to be ditched. Other games, like the Sonicthe Hedgehog series and, specifically for this site, Castlevania had a harder time replicating what was magical in 2D without getting bogged down in weird 3D ideas.
All this is a contributing factor, then, as to why Reinhardt Schneider isn't a well remembered Castlevania hero despite technically showing up in two games (Castlevania (for the Nintendo 64) and Castlevania: Legacy of Darkness): those games just weren't very good. While we at the Inverted Dungeon have a soft spot in our hearts for Reinny's titles (and, thus, for the hero as well) even we will admit his games weren't that great. So while other heroes come and go in the series to memorable effect, ol' Reinhardt disappeared with little fanfare to make his passing.
Castlevania (for the Nintendo 64)
Although not a direct decendent of the Belmont line, Reinhardt was related to the clan and had at least a little of their famed blood in his veins. That's why his family, the Schneider clan, came to possess the whip after the Belmonts mysteriously disappeared. Trained from an early age by his father, Reinhardt knew that he could have, one day, gone up against the vampire lord Dracula (which, considering Castlevania continuity, it sometimes felt like the Dark Lord was coming back on alternating Tuesdays).
His dedication to training did eventually pay off as, eventually, the dark castle of Dracula one again rose from the mists of Romania. Heading off into the outlands of the fotress, Reinhardt fought his way into a deserted villa. There he encountered a young woman, Rosa, who wandered the forgotten halls late at night. As he soon learned, the lady was, in fact, a vampire -- although a seeming unwilling one. They conversed briefly before she wandered off (probably to unwillingly feed on humans and unwillingly lament how much being an eternally attracive and immortal being really sucks).
That wasn't Reinhardt's last encounter with the woman, though. Within a matter of hours the vampire hunter managed to get into the castle proper, and while exploring the central halls he came upon the girl once again. Falling victim to the dark magics of the castle, Rosa lashed out at Reinhardt. The two engaged in a pitched battle but instead of killing the vampiress, Reinhardt recognized the good within her struggling to get out. He bested her but spared her life hoping that once he killed Dracula she would somehow be freed.
Meanwhile, during his explorations, Reinhardt also came upon a young boy named Malus who seemed to be fleeing the forces of darkness. Although their initial interactions were brief, it was eventually revealed that Malus would be the host to the demon lord's power. Once Reinhardt fought his way to the top of the castle he fought with with a false Dracula. It was only as he escaped the crumbling upper towers that Reinhardt came upon the true evil lord, Malus ne Dracula, and the two engages in a bitter fight to the death.
Reinhardt was the victor of the battle, though, striking the fatal blow that sent the foul demon back to Hell. As the castle crumbled, Reinhardt rode off into the sunset with a now freed, human Rosa so the two could (as it was implied) live a long and happy life together.
The Nintendo 64 Castlevania technically had multiple endings, good and bad, that despicted what happened to the heroes if the did or did not defeat the true Dracula (Malus). Of course, only the good endings are in continuity (largely because the bad ones depicted Malus still alive with the power of the Dark Lord within him, something that clearly never came to pass in the later games in the series). Not that continuity is easy to pinpoint with these games -- they hold a nebulous place in the series at best and, generally, are considered non-continuity titles at this point (not that we ever pay attention to pesky things like that here).
Technically Reinhardt shows up in two games but the latter, Legacy of Darkness, was considered a director's cut of a sort for the original title. That game featured a main quest starring a different hero, Cornell. Originally Cornell was slotted to show up in the first version of the game but was cut due to time constraints. His adventure was restored in Legacy and then Reinhardt's adventure was added in as an unlockable. Some minor things were changed (such as which levels were in the adventure) but the two versions are, more or less, the exact same game (with the exact same plot) so, as far as Reinny's history is concerned, they're the same title.
It's also worth noting that originally Reinhardt was named "Schneider Belmont" during development of the first N64 game. His name was changed for who knows what reason, but eventually it tied into IGA's plans to have the Belmont disappear from history at a certain date. Although this game has a nebulous place in Castlevania continuity, Reinhardt does fit nicely in his current form and clan-connection.
Playing as Reinhardt:
As a Belmont relative, Reinhardt largely controls like other heroes in the clan(s). He comes with a standard whip and sub weapons as you would expect, although to make him more playable in 3D, all of his main weapons have a lock-on feature to make them easier to use. He also came with a smaller dagger he could use for up close combat (which, amusingly, was an item a number of other heroes, like Richter and Sonia had in their artwork but never actually use in their games).
While he came well equipped, Reinhardt wasn't all that great to control... which, actually was a lot like the slow-as-molasses Belmonts that came before him (looking at you Chris). Making matters worse were the wonky controls of the games -- there were a number of platforming sections that required the heroes to grab ledges but the hit-detection was spotty leading to a number of times where the hero would grab for the ledge, miss, and then die. Great fun.
It's not hard to see, then, while Reinhardt isn't exactly beloved in the Castlevania community.