Marauder Shields

Marauder Shields was the evil mastermind behind the Reaper invasion of the Milky Way Galaxy. A synthetic-organic creature created from harvested turians using Reaper technology, Marauder Shields had kidnapped Blasto the Hanar Spectre (the Council's best Spectre) as part of his plot to destroy all spacefaring organic life.

He then indoctrinated Commander Shepard (the Council's second-best Spectre) in an attempt to eliminate the two newly-recruited Spectres sent to rescue Blasto: Dick Rider and Johnson Hopper.