User blog comment:H-Man Havoc/New Squadmate Species for ME3?/@comment-743796-20101229160023/@comment-1074875-20101229170539

Like you wrote: "majority were Cerberus..." (in regards to humans killed). the fact that Shepard hunted down Cerberus organization in a series of assignments throughout Mass Effect did not stop him being recruited in ME2 (although I personally thought that this development ruined Shepard's character somewhat).

Shepard can kill some batarians, and spare others - the character can be merciful, vicious, or apathetic depend on the player choices. Shepard may also change attitude throughout the Mass Effect series (many of the aliens he encounter do...)