After the relative success of Castlevania: Harmony of Dissonance, Konami had to figure they had a winning formula for the series going forward: make a big, explorable castle loaded with goodies and within it slap a hero who looks like Alucard just enough to please fans. Then, just wait for the money to roll in. Since it worked with the last hero of the series, Juste Belmont, it had to seem pretty easy to do it all over again.
What Konami did right with their next game, Castlevania: Aria of Sorrow (and it's hero, Soma Cruz) was to find a way to just embrace the Alucard-like qualities, going whole-hog with what worked previously and saying, "yeah, screw kicking it up to eleven. Let's just ramp it up to twenty." To that end, Soma (college student and savvy dresser) collects all kinds of weapons, find all manner of monsters, and gains a multitude of magical abilitites from the souls of monsters. He's a versatile vampire hunter and as close as the series ever got to making a second Alucard... and that's because (spoiler) he's actually Dracula.
Give them credit: Soma is the first hero to never have to fight Dracula because, deep down, he has the reincarnated soul of the Dark Lord inside him. That's why he can gain more powers over time, why he can learn to master the abilities of monsters. Being Dracula was a fresh, interesting twist for the game that also actually explained all the weird quirks the Metroidvania had tried hard to ignore up until now. It just worked.
Castlevania: Aria of Sorrow
Soma, foreign exchange student, was living in Japan for some time, furthering his studies. During that time he'd struck up a friendship with a girl in his school, Mina Hakuba. During the first reported full solar eclipse, the two decided to venture to the nearby Hakuba Shrine so they could watch the splendor of the event. However, instead of witnessing the eclipse (and probably burning out their retinas -- remember to practice proper visual safety, kids), the two were magically transported into a strange castle. Yes, Dracula's castle.
Acting protective of Mina, Soma ventured into the castle alone to find an escape for the two of them. There, however, he was beset by monsters. Killing one of them freed it's soul which Soma seemingly absorbed. When this happened a dark stranger, Genya Arikado, stepped out of the shadows. He told the young man that Soma had the Power of Dominance, the ability to control and absorb the souls of the monsters within the castle. As Genya explained, the castle needed a master, someone to control the dark magics within. Years before, in 1999, the castle had been sealed with an eclipse and it's master, Dracula, was finally destroyed. Now, though, with a new eclipse, the castle had returned as was desperate to find anyone with the Power of Dominance that could be its new master. Soma would have to venture deep into the castle, destroying any threats he came across, all so he could seal the magic of the fortress away and find a way out of the demon castle.
Delving deep based on Genya's advice, Soma met many other strangers along the way. There was Hammer, the soldier-turned-vampire hunter-quickly turned salesman who setup shop near the castle entrance and aided Soma whenever the young man had spare cash. Then there was Yoko Belnades, a warrior for the Church who had ventured into the castle in an attempt to find a way to keep Dracula's sealed within forever. She and Genya were allies, and Soma continued running into the two of them throughout his journey. And then there was the mysterious vampire hunter, J, who had lost his memory some time ago but knew he had to be in the castle to stop whatever dark magics were lurking.
One other person roamed the halls of the castle: Graham Jones. Born the day of Dracula's death, Graham thought he should be the heir to Dracula's power, that he was the Dark Lord reborn. The castle did respond to himn, granting the man some power, but Graham craved more. Seeing Soma in action and sensing the power the boy controlled, Graham swore that he would kill Soma and steal the boy's power for himself, thus ensuring his ascention as the true Dark Lord. He repeatedly provoked Soma, hoping the lure the boy into a fight he couldn't win.
But what Graham didn't anticipate was how powerful Soma would become. The the young man wandered the halls, collecting souls, he discovered the power of his dark gifts. After tussling with J (who turned out to be Julius Belmont of the famed Belmont clan), Soma unlocked his full potential, but also proved himself to be a good man -- he let J live, refusing to end their fight in bloodshed.
With J's urging, Soma went to the castle keep to face off against Graham. There, using the powers of Dracula, Soma bested the false Dark Lord and proved that only he was hte true heir to Dracula's throne. Soma wasn't finished, though. After consulting with Genya (who Soma now realized was Alucard, Dracula's son), the two agreed that Soma would have to travel into the Chaos Realm, the zone where the castle drew its true power. Within this pocket dimension Soma came up against the source of Dracula's magic -- the entity Chaos. He faced off against this foe, too, in a fight that drew every skill and technique he could muster.
With the soul of the castle itself defeated, Soma, Mina, and the rest of the forces for good left the castle assured that this time, for sure, Dracula was truly laid to rest.
There are actually a couple of endings in Aria depending on if Soma gains the "true power of Dracula" and uses them during the fight with Graham. By equipping the Giant Bat (transform into a bat), Succubus (heal by dealing damage, i.e. drinking blood), and Demon (there are a couple that fufill this, but they all turn Soma into a hulking demon when used), Soma proves himself to be Dracula in the flesh and, thus, inherits the power of the castle which then grants him entry to the Chaos Realm (after killing off Graham). However, if he doesn't equip these souls during the fight with Graham, the game just ends after that battle with the question lingering "will Dracula ever come back again?"
Like other Metroidvana games in the series, Aria has a couple of modes. There's a Hard mode that can be activated where the enemies take (and deal) more damage. There's also a New Game + mode where Soma carries over most of his souls and items but not levels or game time. Then there was Julius Mode where the player took on J, playing him through the castle (in a mode very much like Richter mode from Symphony of the Night. This mode would be greatly expanded in Aria's sequel...
Castlevania: Dawn of Sorrow
One year after the events of Aria of Sorrow, a new cult, With Light, has arisen. Lead by Celia Fortner, this group intends to resurrect Dracula as the true source of evil -- true good can only exist with true evil to balance it, or at least that's their throught. To that end the cult built a massive castle (a replica of Dracula's) and used it as a lure for Soma. They hoped to kill Soma in the castle, thus releasing the dark magic within him so that one of the other two potential Dracula candidates they found, Dimitrii and Dario, with take posession of the power and become Dracula instead.
Celia confronts Soma and Arikado early on, before the young man is even at the castle, luring him into action against the cult. Arikado (enimgmatic as ever) shows up to warn Soma off of venturing to the castle, fearing that if Soma were to get involved Dracula's power would be unleashed (on way or another). Soma, though, ignored the warnings and went off on his own (leaving Mina behind for her own safety). Inside the castle, Soma met up with a few old friends. Yoko Belnades once again arrived, there to give Soma aid in the magical arts. She advised him on the magical seals blocking his path through the castle, telling him how to break them. She also provided magical upgrades for his weapons (in exchange for the magical energies of the souls he collected). And, of course, if a shop was setup the Hammer would be around, once again showing up to sell his wares and collect a little green.
Soma, too, met up with Julius Belmont who was once again patroling a dark castle, working to prevent the resurrection of Dracula. Like Arikado, Julius feared what would happen if Soma vantured too deep into the castle. Of course, when Arikado showed up, he gave Soma an earful about how dangerous it was for the young man to bring the pwoer of Dracula into the dark abode. it being too late to stop him, though, the older vampire warned Soma against giving in to his dark desires.
Staying on the side of good was difficult for the young man, though, as the two disciples of the cult were after him. Dimitrii was the first to confront the Soma, forcing the young man into a battle to the death, Dimitrii seemingly falls in battle, his soul getting absrobed by Soma (even though Soma didn't think he could absorb human souls, only the souls of demons); this caused Soma some strife and worried Arikado to no end. Then Dario came after Soma, using powerful pyrokinetic abilities to try and defeat the young man. Although Soma handily bested Dario at first, Celia quickly appeared and teleported the two away, leaving Soma with a cryptiv invitation to meet them at the pinacle.
It was again, at this point, that both Arikado warned Soma not to pursue the battle any further, by he would not be dissuaded. Arikado provided Soma with a letter from Mina, sending her love and protection, as well as a special talisman. Soma took the note, and the talisman, and then ventured on, eventually working his way to the pinnacle and taking on Dario again. By this point, though, the supposed candidate for Dracula's power had become even more powerful, absorbing the sould of Aguni, enhancing his fire abilities. Worse, still, was that Celia and Dario had a trick planned for Soma, a doppelganger of Mina that they would kill, potentially causing Soma to lose control and give in to his dark nature. The two cultists didn't know about the talisman and Soma saw through the ruse.
Venturing into a the mirror realm, Soma was able to fight the very soul of the demon Aguni itself (in a mirror realm), freeing Dario of its power which also ended up robbing the man of his fire abilities and his connection to Dracula's power. Defeating Aguni, though, had a strange side-effect -- the soul of Dimitrii, which had been within Soma this whole, was unleashed. It had copied the Dominance ability from Soma (the very thing that allowed Soma to absorb souls) and, free of Soma, it possessed the doppelganger's body, resurrecting Dimitrii. He, along woith Celia, fled once again, this to the castle's Abyss where the final confrontation would take place.
At the entrance to the Abyss, Soma encountered Arikado and Julius once more. It was with Julius's aid that a dark barrier blocking access deeper into the castle wass destroyed, allowing Soma to head to the final section of the castle. Diving into the Abyss, Soma finally met up with Dimitrii and Celia once more. Things had not gone with for Celia by that point, though, as when Soma arrived, Dimitrii had crucified the sorceress. With her death, Dimitrii was able to unleash the true power of Dominance within himself. However, he was unable to control the power (and all the souls he had, by this point, collected) and the power overtook him, transforming him into the Menace, a hulking beast of dark magics. Soma had to defeat the creature to end the threat of it's power (and Dracula's influence) once and for all, which he did via a long and torturous battle.
In the end, with the cult defeated, the heroes gathered outside of the castle. Joined by all their allies, and Mina too, the heroes discussed the future which seemed much brighter than it had before. Soma and Mina acknowledged their feelings for each other, and everyone was assured that Dracula was finally, permanently, laid to rest.
As with Aria, Dawn of Sorrow has alternate endings and story modes. The most interesting one happens if Soma fails to equip the talisman from Mina. Here, instead of seeing through the doppelganger ruse, Soma gives in to his dark nature at the sight of Mina's death. He then goes on a rampage, killing Celia and taking over the castle as Dracula, the Dark Lord. This story thread is then picked up in "Julius Mode" wherein the Belmont is joined by Yoko and Alucard as the three explore the castle together. "Julius Mode" is very similar to Castlevania III in play style and quite enjoyable. Unlike previous story modes, though, there are cut-scenes and story bits through out (and not just heroes silently exploring a castle that wasn't meant for them). The heroes even confront Dracula-Soma at the end, having a full battle with the Dark Lord. It's a great mode for a non-continuity story and an awesome addition to the package.
Castlevania: Harmony of Despair
Soma appears in Harmony of Despair as one of the starting characters in that game. He plays largely like his Dawn incarnation, gaining souls and power as he moved through the game.
Playing as Soma:
In his first game, Aria of Sorrow, Soma controls not unlike Alucard (from Symphony of the Night). He explores his castle, collecting weapons and items and gaining cool vampire powers that aid him in further exploration. Unlike with Alucard, Soma gains these abilities via Tactical Souls, his main source of power. The souls came in three varities: Red Bullet Souls (which acted like subweapons), Blue Guardian souls (special abilitites that could be turned on to defend Soma), Yellow Enchanted Souls (which provided passive abilities when equipped), and Silver Ability Souls (active souls needed for exploration). These souls could be collected from any enemy in the game so there was benefit from going out and trying to kill every enemy to gains its soul. Soma could gain most souls multiple times, too, although this only powered up one item -- aside from this, though, collecting multiple souls didn't help him.
The second time around, though, Soma did benefit from multiple souls. In basic style Soma controlled the same -- the souls he could collect were different (based on a different selection of enemies in the sequel), but the basic idea behind their collection (and use) was the same. This time, however, the more of a soul he collected, the more powerful it could become. Plus, Yoko was available early on in the game, running a weapon's shop. If Soma traded in his collected souls the sorceress could create powerful weapons for Soma to use. These simple tweaks served to benefit the game, giving the soul collection mechanic more meaning and usefulness.
For Harmony of Despair Soma came back with the ability to collect Red, Yellow, and Blue souls and power them up as he gained more of them (thus encouraging grinding in the game). Silver Souls were not included though, as nothing in the castle were ever truly locked off to the characters (so Silver Souls and their key-like requirements were not needed). Plus, the selection of souls available in the game was not a large as in his original titles.