Short answers, pulled from the story.
Narita won the Gold Prize in the 9th Dengeki Novel Prize for Baccano!, a light novel series set during Prohibition-era America. The prize recognized work involving alchemists, gangsters, and an immortality elixir in 1930 Manhattan.
The Naritaverse is a shared universe coined by fans that encompasses Narita's first four light novel series: Baccano!, Etsusa Bridge, Durarara!!, and Vamp!. Each series features fantastical elements within an otherwise grounded social world, and the stories share characters and connections across titles.
Two separate Durarara!! anime television series were produced. The first aired in January 2010 and the second began in January 2015.
Baccano! is set mostly in a fictional United States during the Prohibition era and follows alchemists, thieves, Mafiosi, and other characters whose lives intersect after an immortality elixir is recreated in 1930 Manhattan. Its anime television adaptation aired in 2007.
Dead Mount Death Play is a manga by Narita illustrated by Shinta Fujimoto, serialized in Square Enix's Young Gangan magazine since 2017. It follows a necromancer called the Corpse God who is reincarnated into the body of a boy named Polka Shinoyama in modern-day Shinjuku and integrates into the Shinjuku underworld.
Narita's works consistently feature an ensemble cast of characters, each with their own viewpoint chapters, whose lives intersect due to a supernatural entity. Conflict between characters escalates as their paths cross in unpredictable ways.