Fantastic depiction! First thing I noticed was the forehead - it feels like it needs a bit more texture and smoothing out on the midtone and highlight area. That may be where the brush strokes are most apparent. Otherwise, a very well balanced composition.
She's just as power hungry and ambitious like the Frank Underwood. The original deal is "be the mouth piece and no question asked" and she got greedy. Did you really think she wants justice for Peter? She wants fame and/or leverage over Frank. The moment Frank offering her something more, she backed off from her "pursue of justice" and willing to deal with Frank, start over. She died not because Frank is evil, everyone is evil, but because she's not smart enough, she got outplayed. That's all.
Photoshop default hard round with pressure and shape diameter set to pen pressure, and flow set to 60%. I had tried to use costume brushes, but always end up going to back to the default hard round. LOL.