(Capcom's primary storyline)
D-Type was a line of human bioweapons developed by The Connections. The manufacturer created its line of weapons by altering the genome of human females while in their embryonic stage, and their age accelerated after birth to give the approximate appearance of a ten-year-old girl. The decision behind the appearance was to allow them to infiltrate cities posing as lost children or refugees.
A total of eight D-Types were created by The Connections: Dana; Dahlia; Darlene; Dorothy; Dolores; Diana; Daniella, and Doris. Of these, three were killed in an apparent murder-suicide; four died of natural causes, and another was killed by her creators after being branded a failure. Four of the bodies were transported on the Annabelle with Eveline, the first E-Type, when The Connections abandoned their lab. These were two unidentified newborns; Dolores and Dahliia. When the ship ran aground in the Louisiana bayou, they were recovered by the Bakers. Dolores and Dahlia proved useful in the creation of a medicine to resist Eveline's control over infected people.
The D-Type series developed in collaboration between The Connections and Miranda, the foremost researcher on the Mold, with the goal of creating a commercial human bio-weapon capable of mind-control. For the human base, The Connections produced eight genetically-modified clones of Miranda's daughter, Eva. These clones were subject to rapid aging which could only be halted with regular medication upon reaching physical development equivalent to a ten year old girl. Before reaching Stage 4 of embryonic development, these clones were infected with a modified Mold species.
Unlike humans altered by the naturally-occuring Mold, D-Types were capable of directly manipulating quorum sensing. An enemy combatant exposed to the Mold would develop a fungal mass in the brain, and through quorum sensing, would become rendered suggestible and prone to hallucinations, effectively collapsing the enemy's ability to wage war.