Short answers, pulled from the story.
Reuben Langdon has voiced and performed motion capture for Dante since Devil May Cry 3 in 2005. Drew Coombs voiced the character in the original 2001 game. For Japanese releases, Toshiyuki Morikawa has provided the Japanese voice.
Dante is named after the Italian poet Dante Alighieri, author of the Divine Comedy. Series creator Hideki Kamiya rewrote the original game's story drawing from the Divine Comedy.
Dante was designed by Makoto Tsuchibayashi under the direction of series creator Hideki Kamiya. Yuichiro Hiraki, formerly of SNK where he designed King of Fighters characters, handled motion capture and contributed to the fighting style.
Capcom told developer Ninja Theory that Dante needed a redesign to appeal to a younger demographic. Italian concept artist Alessandro Taini, known as Talexi, created the new look, which drew inspiration from Christopher Nolan's film The Dark Knight.
Vergil is Dante's identical twin brother and recurring antagonist in the series. In Devil May Cry 3, Vergil tries to reopen the portal to the demon world to obtain their father Sparda's full power. In Devil May Cry 5, Vergil is also revealed to be the father of Nero.
Dante was originally called Tony Redgrave during development. The name was a reference to Resident Evil character Chris Redfield. The alias is still preserved in the inscription on Dante's handguns Ebony and Ivory: "For Tony Redgrave, By.45 Art Warks".