While the galaxy was able to experience a moment of triumph, the Reaper problem wasn’t solved in the original Mass Effect. In its sequel, these massive constructs are making a bit of a return, but not in a traditional way: the Reapers are influencing and creating new enemies that Commander Shepard and crew will have to face.
In the above developer diary for Mass Effect 2, we’re shown a few new enemies that will debut in the game. The first of which are the Collectors, an advanced race of beings who are kidnapping entire colonies of humans. As explained, they roll in a perhaps Reaper-enhanced ship and use bugs to subdue their victims. The latter bit of information is fitting for the characters — these dudes look like insects themselves and are connected to some sort of hive mind like bees or whatever.
Other enemies introduced in the trailer are weird human-infused Husk abominations, as well as a wicked large robot, which looks like a sci-fi improved version of an ED-209. (Think about it.)
And then there’s Legion, a Geth disconnected and obsessed with Shepard. We may have seen him before in the first teaser trailer for Mass Effect 2, which brings all of this totally full circle, man. Full circle.