Agent Felix Blake was an employee of the S.H.I.E.L.D., and the former partner of Phil Coulson.

He is both arrogant and very much by-the-book, and appears to remember a Phil Coulson who was more in that mold. He suggests strongly that S.H.I.E.L.D. will not tolerate indefinitely Coulson running his own show his way, although he backs off visibly when Coulson fails to back down.

He first appears in the MCU, and mentions Agent Coulson, in the Marvel One Shot Item 47.

Despite his reservations concerning the changes in Coulson, he answered the call to meet on "the Bus", and was partnered with Agent May to track down Thomas Nash. The duo had a run-in with Deathlok, but despite sustaining very serious injury, Blake had the presence of mind to use a tracker round on his assailant, allowing the other agents to use GPS to ascertain the cyborg's location. When last heard of (in Season One), he was described by May as "in critical condition".

In Season 3, it was revealed that the injuries Blake received from Deathlok damaged his spine and paralyzed him from the waist down. By time Blake had gotten out of the hospital, Hydra had already destroyed S.H.I.E.L.D. and Blake developed a hatred for all powered people.

In "Watchdogs", a domestic terrorist organization called the Watchdogs attacks a ATCU storage facility with a weaponized form of a chemical called nitromeen. It's later discovered Blake is the leader of the Watchdogs and supplied them with the nitromeen.

Coulson and Lincoln check old safe houses that Blake used when he was a S.H.I.E.L.D. agent and eventually find him in Atlanta, Georgia. Blake points a gun at them and makes a speech about how powered people need to be stopped and agencies like the ATCU and S.H.I.E.L.D. only protect them. Lincoln then throws a bolt of electricity at Blake, only to learn Blake was a hologram the entire time.

At the end of the episode, a wheelchair-bound Blake has a meeting with Giyera. In exchange for destroying the ATCU facility, Giyera agrees to supply the Watchdogs with weapons.