Castlevania: Dawn of Sorrow
One year after the events of Aria of Sorrow, the followers of Dracula were once again trying to bring the Dark Lord back from the dead. Another cult (of cultists, obviously) lead by the evil sorceress Celia (apparently separate from the cult lead by Graham Jones in the previous game...or the band, The Cult), gathered at Celia's castle (which is a pretty decent analogue to Dracula's own castle) to either find a way to kill Soma Cruz (who is actually Dracula, but doesn't want to be evil) and free Dracula's soul for a new host (they have two, Dmitri and Dario, ready for at shot at glory), or make Soma embrace his "true" fate.
Instead of just happening by, Soma took the initiative and went to Celia's castle to confront the evil cult head-on. Other characters -- such as Yoko Belnades, Genya Arikado, Julius Belmont, and (the ass-kickin' merchant) Hammer -- were at the castle as well. Hammer and Yoko served as merchants, selling Soma weapons and items (Hammer) and allowing him to fuse collected souls to his weapons to make them more powerful (Yoko). Meanwhile, Julius and Genya are encountered throughout the castle, providing information about the various situations and villains encountered in the game.
The two Dracula potentials, Dmitri and Dario, each attempted to kill Soma in turn. Potentially due to their not being the real Dracula, they are unable to complete the task. Soma gained more power through them, and eventually found his path to Celia chamber. Although Celia tried to fool Soma, killing a doppelganger of Soma's friend Mina Hakuba in an attempt to make Soma switch to his evil side, Soma resisted the lure and stayed true to himself. A final battle with Celia ended with Soma the victor, but the adventure wasn't quite over yet.
To get Dmitri up to "full" power, Celia and Dmitri journeyed to the "Abyss". There, they collected the souls of various powerful demons to give Dmitri the powers to emulate Dracula -- in hopes that he would serve as a proper vessel in this form. Unfortunately for Dmitri, he was just a copy of the true power of Dracula, and wasn't truly able to control these souls. With Julius's help (in breaking a seal to the Abyss), Soma was able to venture into this dark realm. There he encountered the souls that Dmitri stole, which had gathered together into a giant demon (really, a flesh golem). Soma had to defeat this demonic mass to destroy the last of the dark energies in Celia's even fortress, and rid the world of another potential threat.
The day saved, all heroes fled the castle. Soma was reunited with Mina, everyone had a good chuckle at the "love birds" (because ribbing Dracula always seems like a good idea), and the world was safe in the knowledge that, once again, Dracula wouldn't be coming back any time soon.
As in Aria of Sorrow, Dawn of Sorrow features a bad ending: normally, Mina will give you a charm to wear, and if you confront Celia with that charm equipped, Soma will see through Celia's ruse. If you don't equip it, though, Soma will be fooled, and will become the Dark Lord (over the death of his love -- an allusion to Dracula going evil over the death of his wife).
The cool thing is that, as in the first game, Julius is a playable character. Here though, you unlock Julius by having Soma become the Dark Lord. Julius, with the help of Yoko Belnades and Genya "Alucard" Arikado, will then go on an adventure to defeat the new Dark Lord of the castle, Soma Cruz. While non-canonical, this mode as awesome and benefits from having an actual complete plot (unlike so many other bonus-character modes in the series).
As with the previous game, Hammer is once again included in the cast, but he doesn't get to play a role in "Julius Mode". Leftover data in the ROM of the game has revealed dialogue that hints Hammer might have also once been a planned playable character -- in terms of Castlevania III, Hammer would have been the Grant DaNasty analogue to Julius/Trevor, Yoko/Sypha, and Alucard... Alucard.
This isn't the last time Hammer will get screwed by tight timelines and budget constraints (we presume). He was also planned to be in Harmony of Despair as a downloadable character. Sadly, with that game not being the success Konami apparently hoped for, Hammer was once again left on the cutting room floor.
To correct this obvious oversight, the editors of the Inverted Dungeon are currently writing a pilot for Hammer & Shaft: Courtroom Crusaders! that we hope will give Hammer his proper dues.