Castlevania: Lords of Shadow
For the longest time one man was in charge of overseeing the Castlevania series: Koji "IGA" Igarashi. His tenure essentially started with Castlevania: Harmony of Dissonance, although his first game for the series came out a few years earlier with Castlevania: Symphony of the Night. It was through his stewardship that the series saw its evolution from old-school action/platforming to Metroidvania adventure titles and, for a certain contingent of the fan-base, also saw its greatest artistic evolution.
After years shepherding the series, though, Konami elected to take the series in a different direction. This is presumed to be because while the series managed to maintain consistent sales numbers, the fan-base wasn't growing and "consistent sales" weren't the same as "good sales". IGA left the company over the decisions so he could pursue his own projects while Castlevania was handed to another Konami all-star developer, Hideo Kojima, director and overall creative head of the Metal Gear franchise. Kojima was given one direction: take the Castlevania series and make it into the Triple-A title Konami wanted (but, very rarely, the series actually achieved).
Kojima, along with his studio Kojima Productions, went looking for a new studio to shepherd the Castlevania franchise under Kojima's direction, and the eventual team that was brought together, from developers Mercury Steam and Team Ninja, set about rebooting the franchise. The threw out all the old continuity that had been built up since 1987 (much to the howls of protest from the dedicated, hardcore fan-base) and worked to craft an all-new story that anyone, old fan or new, could get into immediately without having to wade through twenty-plus games worth of story and history.
The resulting game was Castlevania: Lords of Shadow (titled Kyassuruvuania Rodo obu Shado in Japan, which is just a phonetic Japanese version of the English title), an entry that broke from all conventions of the previous series (and not just its history). Introducing a new hero, Gabriel Belmont, this whip-wielder was a warrior of the Brotherhood of Light, sent to battle the titular Lords of Shadow and save the world. There was no Dracula (at least, not immediately), no castle high up on the Borgo Pass, and none of the classic 2D game play fans knew so well. In its place was a game that borrowed heavily from the play style of God of War and its ilk, making it a very odd fit for the previous franchise.
For fans this game felt like a stark change from everything they knew and loved. Little was left in Lords of Shadow that fans would recognize beyond a Belmont carrying a whip (and that whip wasn't even called the "Vampire Killer"). Gone was the Metroidvania emphasis on exploration, instead leading to a much more linear, action-heavy game. Many fans were disappointed, too, in the way the game played, feeling that the 3D game play lacked anything that resembled classic Castlevania action. That was true, and a frequent comments from reviewers at the time as well, but then the same criticisms were leveled at Castlevania: Lament of Innocence (noting that games similarities to another 3D action series at the time, Devil May Cry).
That, of course, raises the question of once you remove Castlevania from its roots, pulling it out of 2D into 3D and breaking the conventions of the series, does it even really count as Castlevania anymore? What are action games but clones of each other, at some point or another, and to be considered "Castlevania", wouldn't some of what made the game special needs to be maintained? MercurySteam and Team Ninja didn't think so, and Lords of Shadow played like a game designed for people other than Castlevania fans.
Despite the rock reception from the vocal fan contingent, though, Lords of Shadow proved to be a big success for the series, becoming its top seller ever, with over 1.75 Million units sold over its life (beating out the original Castlevania, even with re-releases added to the numbers). That was the kind of success Konami wanted for their series, and that success lead the company to immediately put two more games in the Lords of Shadow series into production: interquel Mirror of Fate, and true sequel Lords of Shadow 2.
However, not everything was right with Konami after this. Lords of Shadow would be the only one of the three games to feature the direction of Kojima and the involvement of Team Ninja. After this, MercurySteam would take over full duties. This was, in part, due to behind the scenes issues with Kojima, issues that eventually lead to the developer leaving Konami (just as IGAA had done previously) so he could pursue is own weird ideas (like eventual release Death Stranding). The first Lords of Shadow would also prove to be the only hit for this trilogy, as both follow up titles massively under-performed in comparison to the opening title.