It was said that Yaroslav was a very calm-mannered and good-natured man which helped him find a likewise mind in Ilya Pasternak amongst the more fiery and strong personalities of other Vampire Team members.
Estovakian Civil War
During one of his sorties, Deryagin was shot down by the Strigon Team and was placed into the Vampire Team where he fought as a member of the Eastern Faction. This occurred shortly before the decisive battle between the Eastern Faction and the Lyes United Front.
During Emmeria's assault on the Chandelier, Deryagin led one of the two Chandelier Defense Team squads into battle. He flew a three-man formation in the Chandelier Defensive Operation while Aleksei Cheshenko led a squad of the other four Strigon survivors. Both Deryagin and his two wingmen were killed in the ensuing battle.
- Yaroslav Deryagin is the second pilot to use the callsign Strigon 3 during the Emmeria-Estovakia War, the first being Karlo Bogdanovic.