Dion
character in the Transformers series
Dion Blaster
character in video game 1080° Snowboarding
Decker Moss
character in soap opera "General Hospital"
Decimus
character from the Heroes of Olympus series
Lord Decimus Tite
Barnacle of the Circumlocution Office, in "Little Dorrit" by Charles Dickens
Maximus Decimus Meridius
main character in movie "Gladiator"
Deep
character on TV's "Quantico"