This might seem like an obvious pick for the top spot - the show is called The Punisher, after all. However, the heroes of previous Marvel-Netflix shows haven't always been the best character on display (need I remind you of Iron Fist again?). In this case, though, Frank Castle is far and away the best thing about his own series.
A great deal of that is due to Jon Bernthal. As mentioned earlier, the current climate could make it tough to feel anything for Frank, but Bernthal manages to make us care thanks to the nuance he imbues his performance with, which allows us to see an unexpected amount of humanity beneath the Punisher's armour. The Defenders shows are stuffed with terrific actors, but Bernthal's performance in this season is one of the finest of the bunch.
The writing also serves Frank well as he even goes on a kind of journey of self-discovery across the run, ending it by talking through his problems at a support group. Hopefully he hasn't worked through all his issues, though, so that we can see him don the skull motif again in a follow-up season.