Dante all throughout the game in general. His cockiness is absolutely hilarious.
The opening cutscene. The whole damn thing, starting from the moment Dante punts his chair.
At the start of the second mission, Dante puts on his trademark red coat in the coolest manner possible... Then he sneezes, and the front of his store crumbles completely.
Dante mouthing off to Cerberus at the entrance to Temen-ni-gru, talking to the three-headed Hellhound like he's a normal dog.
Cerberus: Leave now, mortal! The likes of you are forbidden in this land! You who are powerless are not worthy to set foot here! Dante:Wow, I've never seen a talking mutt before. You know, in a dog show, you'd definitely take first place. Cerberus: You, a mere human, make a mockery of ME?!? [breathes a ray of ice, which Dante dodges] Dante: Eeeasy, Fido. How 'bout I take you for a walk? [claps hands and makes a beckoning motion] Come on, puppy, let's go!
Almost everything that happens when Jester is present. Creepy Awesome, campy and maniacal (complete with Joker-esque evil laugh), appears randomly out of nowhere to give advice, and threatens to spank you during his boss fight. Depending on whether you're afraid of clowns, that is either traumatic or hilarious.
Jester can actually get tired out while dancing and dodging gunfire. This is demonstrated briefly in a cutscene, and the player can take advantage of this tactic during his bonus boss fight.
Jester mocks Dante whenever the latter is stuck while exploring the tower, but his delivery is also hilarious:
Jester: Write it down on your HAND if you don't trust your HEAD.
He also describes the Temen-ni-gru tower using an innuendo:
Jester: You saw it too, didn't you? That huuuge tower, jutting out of the ground. That thick shaft that causes women to SHUDDER!
Every time Jester approaches him, Dante sticks a handgun to the clown's long nose, temporarily folding it down.
Jester actually "bleeds" confetti whenever you strike him during his boss fights. It's hilarious, but it also fits his clown theme.
After Jester has spoken too much during their second encounter, Dante threatens to shoot him, with the reason that Jester talks more than him:
Jester: Whoa, whoa, whoa... You're not going to shoot me, are you? If you do, I'll die, you know? Dante: If that's what it takes to shut you up. It bugs the crap outta me when someone talks more than I do...!
When Jester knocks Lady to the floor after revealing his true identity as Arkham, he mocks his daughter in a playful tone. What makes it interesting is that the two sons of Sparda are listening, and Jester gets interrupted mid-sentence by Vergil:
Jester: Don't be a bad girl, Mary... Or you can expect a spanking from daddy later! Jester's gonna spank your butt, spank you on the bu— Vergil: Insane buffoon. I don't know where you came from, but you don't belong here.
The exchange when Dante first encounters Agni and Rudra. Dante is trying to get through this chamber when the brothers start conversing on how to entertain their guest. One sigh of annoyance from Dante and Rudra actually asks what a sigh is.
When Dante receives Agni & Rudra. He agrees to take them with him on the condition that they don't talk. Afterward, he does his usual showoffy weapon display, after which:
Agni and Rudra: Impressive. [Dante looks at them, then clonks their heads together] Dante: No. Talking. [silence from the two swords] Dante: ... Good. [sheaths them and walks on]
When Dante leaves the Leviathan's body and is soaked with its blood on his way out, Lady insults him for it, saying that she doesn't want to date a demon, especially a man who's covered in blood. Dante then proceeds to sniff himself. During this cutscene, there's also a brief moment where the camera shows a "Welcome" text and Jester's portrait below it, both written and drawn in blood.
Dante acquires Nevan in badass guitar form. Instant rock show ensues, complete with stage sparks and loudspeakers in what's supposed to be an opera house.
During Nevan’s fight, she will glide towards Dante/Vergil, bringing them into a kiss to drain their health if she reaches them. Notably, the player character, (yes, Vergil will do so) will place their arm around her despite the obvious danger and their health already being drained before the kiss even happens.
There’s also the noises they make throughout the sequence. During the kiss, Dante sounds like he has a bad case of hiccups while Vergil makes angry-sounding grunts. Before said kiss, Dante will make a sigh that sounds rather feminine and Vergil? He makes an abnormal noise that sounds utterly unlike him, like a cat purring in an autotuned deep voice.
After Dante's fight with Beowulf and hearing that Beowulf vows revenge on him thanks to his dad, Dante's not very thrilled about him. Honestly, can you blame him?
Dante: "Why do I gotta take the heat for my father? Come on, man. Cut me some slack."
Dante immediately makes a horse-related pun when he meets the horse demon Geryon.
Dante: Talk about Horse Power.
One after Dante does his midair motorbike-fu thing. He lands inside the tower, unharmed... and the bike explodes. The explosion clears, he looks at the handlebars (which he is holding; the handlebars are the ONLY PIECE left), grunts, and casually tosses them over his shoulder as he leaves. *Clank*.
Dante's reaction to Arkham assuming the form of Sparda:
Dante: It's like staring into a backed-up toilet. Why do you always stick your nose in other families' business? Come on, dude, don't you have any hobbies?
And after Arkham transforms into a horrible monstrosity...
Dante: Come on, dude. My father wasn't so hideous. Can't you tell by looking at me? [looks at his reflection in his BFS]
Vergil snarks at Arkham after he and Dante defeat him.
Arkham: I HAVE THE TRUE POWER OF SPARDA!!!
Vergil: Not very classy for someone's dying words... *Casually tosses Ebony to Dante*
Also the way they trade swords back after temporarily using each other's weapons. They twirl them a bit and then fling them over to each other nonchalantly in unison. It only adds to the stylishness of the entire scene, as does Vergil returning Ebony by tossing it in the air without even looking at his brother.
The funnier one though, is this cutscene wherein Vergil plays with the Neo-Generator sphere like a soccer ball, just as Dante did. This became hilarious enough to spawn the "Vergil Ballin'" memes within the fandom, and it got to the point where Outside Xbox featured and explained the cutscene in their "7 Terrifying Bosses You Got to Play As" video on December 2023.
wherein Vergil plays with the Neo-Generator sphere like a soccer ball, just as Dante did. This became hilarious enough to spawn the "Vergil Ballin'" memes within the fandom, and it got to the point where Outside Xbox featured and explained the cutscene