Arbiter156 wrote...
Shepard only comes into contact with the scientific division during the events of ME2. Shepard destroyed a few Cerberus bases in ME1 belonging to the military division. We have simply no idea how large their military arm was back then. It is logical that TIM has been biding his time since ME2 keeping his military arm hidden. It is only now with the arrival of the reapers that TIM is revealing cerberus's full strength. (also if you have read any of the leak I don't want to know)
Well I have read the leak and I won't tell you to respect your privacy, but Cerberus was considered a small, elite black ops force in ME1 and were portrayed in that fasion until ME2. Although the military sect wasn't featured in ME2, it can be implied that because their organization resorts to terrorist and small cell operations, they don't have the need for a large force.
ME3 being a huge war and all they needed to boost their numbers and they do some things to speed this process.