Doctrine Dark is a playable character in every installment of the Street Fighter EX series.
Born in Germany, "Holger", the man who once served under the orders of Guile with his own special tactical reconnaissance unit. During his tour of duty, his own unit got into a bit of a scuffle with another rival unit, lead by Rolento. The minor scuffle escalated into a full-on battle, with both sides receiving heavy casualties. "Holger" was the only member of his unit to escape. However, he was severely injured emotionally and physically. Outfitted with a portable breathing apparatus, he eventually escaped from the hospital and went into hiding, only to re-emerge as the deranged psychotic killer known as Doctrine Dark. Dark holds Guile responsible for the massacre of his unit. He blames Guile for not training him well, whom he accuses of being more concerned with chasing after M.Bison to avenge Charlie than with the safety of his own men. For these reasons, he seeks to kill Guile as a result.