I noticed they're tough as nails, always seem to do criticals and systematically own any other encounter they appear with.
It's because they never encounter NCR's marauders!
11:34:59 • You encounter: Marauders and Radscorpions.
11:35:01 • You were critically hit for 90 hit points.
11:35:03 • You were critically hit for 165 hit points and were killed.
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10:23:48 • You encounter: Marauders.
10:23:50 • You were critically hit for 104 hit points.
10:23:51 • You were critically hit for 150 hit points and were killed.