One day during a Sparda memorial ceremony of some sort celebrated by
people of the Order of the Sword, Devil Hunter Dante came crashing
through the ceiling and killed the leader of the Order. It turned into
a panic and everyone fled to safety except for Nero, a member and
warrior of the Order, who stayed to fight the mysterious assassin.
Unfortunately for Nero, Dante 'escaped' after their battle and he lost
track of him. Credo, the Supreme General of the Order and older
brother to Kyrie, ordered him to find Dante, and so he set off on a
journey to look for this murderer.
Unknown to most, it was around this time when Sanctus, the leader of
the Order who was just murdered, revived thanks to the "Ascension
Ceremony" (explanation on what it is wasn't given) with the help of
Credo and Agnus, Chief Alchemist of the Order.
As Nero continued to travel, he came across Agnus's lab and met him
for the first time. Agnus planned to kill Nero, though, and they
battled only to result in Agnus's defeat. Nero demanded Agnus for
answers on what was going on, but he got careless and ended up getting
caught and was going to be used as a subject of experiment. So far,
the only answer he got was that Credo was behind all this.
While Nero was knocked out, he had a flashback of the time
Kyrie nearly got killed by a demon, which was the time when his arm mysteriously changed into this devil arm that he possessed. Immediately after the flashback he suddenly woke up and
gained control of the now-resurrected Yamato sword that had been kept
in the lab all this time (reason unexplained). The 'devil' within
Yamato awakened once Nero held it and he used its power to force Agnus
Having freed himself, he continued his journey to find Credo instead
of Dante to seek out his answers. He eventually found him and was
going to ask him what was happening and why when Credo attacked him and turned into
his demon form, forcing Nero into a battle and attempting to kill him
as ordered by Sanctus. Just after Nero defeated Credo, Kyrie came into
the scene to witness Nero's demon arm. Nero tried to explain but Agnus
appeared to interrupt and kidnapped Kyrie as, again, Ordered by
And so Nero continued forth to look for further answers and to save
his girl. He soon bumped into Dante who asked him to return him Yamato
which belonged to the Sparda family. Refusing to comply, they ended up
battling but in the end Dante let the kid keep the sword anyway and
let him go.
Nero eventually found Sanctus who stood on top of a giant statue known
as the Savior that looked similar to Sparda. Now knowing that he was
behind all this. Nero leapt at Sanctus to attack, but Sanctus revealed
Kyrie from within the Savior which promptly stopped Nero from
attacking. Sanctus then summoned the Savior to grab Nero in its hand,
immobilizing him and stealing the Yamato sword in his hand.
Just in the nick of time, Credo came to help and save Nero and his
sister since he realized that Sanctus had betrayed him by using his
sister. Alas, he failed to take Sanctus down and Dante and Trish came
into the scene to see Nero and Kyrie sucked into the Savior to form
his core. It was during that time when Sanctus revealed that Nero had
the blood of Sparda, which was needed to bring life to the Savior, not
that anyone reacted to that revelation.
However, now that the hero is in trouble, it is finally Dante's turn
to save the day, but Sanctus and the Savior had flown back to Fortuna
City to commence chaos. As he ran after them, Dante destroyed the hell
gates that Agnus created using the power of a few devil arms. Knowing
that Yamato was also still in the hands of the enemy, Dante traveled
back to retrieve it, killing Agnus as a prerequisite. Eventually, he
caught up with the Savior and destroyed its core with Yamato,
releasing Nero who was trapped inside.
As Dante continued to battle the Savior outside, Nero fought Sanctus
in his demon form inside and defeated him. Having rescued Kyrie, he
got out of the fallen statue to see Dante greeting them. Nero thanked
him for the help and was going to return Yamato to him when Dante
decided to entrust it to him and left, leaving the happy couple alone
now that he had finished the job Lady got him.