Battle Master Halak Marr was a krogan battle master, biotic, and chieftan of the krogan Halak clan during the Rachni Wars. He was among one of the first krogan to be discovered and initially did not support the cooperation with the Council believing that the krogan united could easily overcome the council. However Marr, a keen political mind decided to keep this hidden and pledged cooperation with the Council. At the same time Marr also supported the creation of the Krogan Union led by Krogan Overlord Tikrog Kurvok, which unified all krogan clans together to help form a super army and with Marr's hope would create a unified krogan people for defeating the council one day. Commanding one of the strongest clans on Tuchanka his forces made up 35% of all krogan forces on Ragnora and 85% of the krogan on Omicron. He commanded his forces from Tuchanka until 83 CE when he was invited to serve as adviser to Kurvok. Known for his political cunning he staged a fake assassination attempt on himself to hurt diplomatic relations with the Manaba and to allow the krogan to help gain a majority share of the Citadel Army. He was later almost killed by the dezban chieftan, Takavor Derishama and was present when the dezba were wiped out. However previously he had hidden away Takavor's tribe on Tuchanka and had begun breeding, cryogenic freezing, and cloning the dezba to form an army for the Krogan Rebellions he had masterminded. As well he took steps to ressurecting Takavor Derishama for use as a leader for his new dezban army.