
Synopsis
Tony is a rough-and-tumble jack-of-all-trades with extraordinary physical prowess and a fierce fighting attitude. His encounter with Gilver, a mysterious swordsman swathed in bandages, changes his life dramatically. He is thrust into the dark underworld of an unsolvable case, separated from the life he knew, and pushed over the edge of desperation. Who's forcing him into a corner? What do they hope to achieve?
Environment
When compared with Devil May Cry 3's, I'd say they're about the same except for major differences.
1. There's actual people around like Nell Goldstein or random mercenaries.
2. Its dark and dangerous, the following pretty much sums it up
"Tony dodged and parried, yet still suffered a number of direct hits. But finally he annihilated his attackers and paused for breath. The dizziness and nausea dissipated, replaced by exhaustion. Tony found it difficult to lift his sword. His spent pistols were little more than dead weights. He realized with a start that if he sat down, he probably wouldn't have the energy to stand back up."
Its more consistent with the spookiness of DMC1's depiction of the underworld.
Characterization of Dante/Vergil

The book does a great job at exploring Dante's past, I like that it explains why he wears red, Dante's emotions, and how he acquired Ebony & Ivory and the Force Edge.
While Dante was playful at times throughout the book, he wasn't an over the top joke like in Devil May Cry 3 or 4. He cared about people especially children.
compare the following
3:30 mins in. To me, it seems like he didn't give a damn about the way Lady felt the the time.
"Remember our proud name. We are----"
"I don't give a ****." Tony stomped on the animated head, smashing it like a melon. His cold sneer was more demonic than anything else in this hellish dimension. But his face quickly melted as he turned toward Jessica, sympathy and fear driving away the rage.
'Does it hurt Jessica?"
There was no reply.
The tiny hands that once made doria were now gnarled roots. Her flesh had solidified into wood. The bell-like clarity of her voice had been replaced by faltering whimpers. But her unchanging eyes remained fixed on Tony. He couldn't stand her tears.
The tree pulsed with life, its black aura pushing out farther with each breath. It would only be a day or two until the demons' reality overwrote the city. No normal human would survive the palpable atmosphere.
Tony gripped his sword tightly. "I' going to end the pain, okay, Princess?
The statement had none of his characteristic sarcasm.
Tony shut his eyes and swung his sword.
An example of his anger
"Tony had erupted at the mention of demons, kicking his stool away. His face had contorted into a mask of fury."
"Tony's arm whipped out and lifted Enzo into the air "Just tell me, Enzo. I'm running out of patience."
Example of him being a great and helpful guy to his friend's remaining family.
"He had used up most of savings opening bank accounts for Grue's remaining daughters."
I like that he's more human and relateable in the book and in DMC1.

Onto Gilver A.K.A Vergil
In the book, he was a bounty hunter before he found Dante. When compared with DMC3's depiction, they're mostly the same minus the one-dimensional craving for power. Gilver is calm, cold, and a bit sadistic
"Gilver unloaded both shells in the he taken from Goldstein's shop. "I guess this is the time I get to be the one to say 'jackpot"
The shells ripped through Dante's legs, sending scarlet blossoms into the air. Dante crashed into the ground in front of Gilver and burbled helplessly. The pain was beyond anything he had ever endured. It stabbed through his mind like a hot poker, preventing all coherent thought. Both of his thighs were shredded beyond use. Blood bubbled up from Dante's mouth.
Gilver stood over his prey, enraptured. "That's a splendid sound. Your agonized expression is quite beautiful." He seemed to drink up the suffering.
My only issue about the book, is that Gilver had no reasons for wanting to summon the demon realm.
Pros
Great exploration of Dante's past and his overall personality.
Explanation on how Dante got his guns
Cons
Lack of motivate for Gilver