Trish is a character who was originally from the game Devil May Cry, and has appeared in every installment of the series, except for Devil May Cry 3.
Trish's personality is hard to pin down as she has changed slightly throughout the games. In the first Devil May Cry, She became excited at the idea about being a "sidekick" at the end, giving her an almost a innocent quality. However in the anime, her personality changes, as she constantly seems to be working for her own gain . This same personality goes over into her character in Devil May Cry 4. Although while disguised as Gloria, she takes on a more refined and humble attitude towards the other members of the Order of the Sword, this is just good acting on her part.