Dario Rosso was an aspiring novelist who was never able to achieve his dreams due to his mother trying to interfere with his life and he subsequently became a wandering salesman who travelled from city to city, often taking his family (including his mother) with him. He checked in to the Apple Inn not long before the
t-Virus outbreak occurred in Raccoon City.
Unfortunately due to the extreme nature of the outbreak his mother, his wife and his daughter were all killed by Zombies and they all presumably became part of the horde. Dario managed to stay alive but became mentally scarred from everything that had happened - the lives of so many had been lost and his entire family were gone. He only had himself, and thus he found a safe place - a Warehouse which was completely locked down and untouched by any creatures.
This changed sometime later when
Jill Valentine managed to break into the warehouse when trying to escape from some Zombies. When she met with Dario, she suggested that he come with her to evacuate but he flat-out refused as he didn't want to be outside with all the swarms of creatures. He then climbed into a shipping container and locked himself in, refusing to get out believing that it would be the safest place for him to be.
As
Resident Evil 3: Nemesis and Resident Evil 3 (Remake) have several open-ended segments, the fate of Dario Rosso is one of them. In one scenario, the warehouse becomes infested by zombies and Dario is found and killed by the creatures, joining the rest of his family as part of the horde. In another, he is simply left in the container and presumably either starves to death or is killed by the resulting explosion when Raccoon City is destroyed by a bomb.
