The show features two assassins, Murphy and Camier, who often tote around machine guns, poisons, have secret "body drop-off" locations including an old incinerator, etc. but despite their job they are protagonists and rarely actually kill anybody throughout the series. When they do kill people, it's more often than not a bad guy, and usually done in a non-graphic manner.
Some scenes of people being beaten up, usually for comedic effect. Rarely is any character seriously injured beyond what would constitute a PG-13 rating.
Murphy and Camier discuss a species of predatory bird that eats the heads off of other birds and leaves them to dry in the sun. This is meant to be funny but may bother some viewers.
Lot's of people are killed mostly with guns . Little to no blood most of the time, but not always. Plus some martial arts fights that are not bloody at all.
The R rating is really unfounded for. It has no way any kind of R rated violence at all. A more correct rating would be PG-13 for action violence.