Gallant
...I can see a few options here.
[5:15 PM]
1. Naga and Darkling are affiliated. Given how little they worked together and how underdeveloped Darkling's power seemed to be, this would probably be a more recent development, such as Naga taking on Darkling after they recently got their powers.
[5:18 PM]
2. 'Darkling' isn't actually a seperate cape - Naga built the minions himself, and we're overcomplicating things.
[5:18 PM]
3. This is just a total coincidence, and both capes just happened to be around at the time.
[5:19 PM]
4. Darkling has a lot more minions than just that half-dozen, and it was just those ones that happened to be in the area at the time.
[5:20 PM]
5. This is an indication that the density of parahumans in Brockton Bay has significantly increased. That this is the new norm.