Daredevil: Born Again Episode 8, titled “Isle of Joy,” is now streaming on Disney+. It answers a key question that has been plaguing the fans since the pilot: Why did Wilson Bethel’s Benjamin “Dex” Poindexter / Bullseye kill Elden Henson’s Franklin “Foggy” Nelson? As the episode unfolds, Charlie Cox’s Matt Murdock / Daredevil gradually unravels the mystery around the murder of his best friend.

Why did Vanessa order Bullseye to kill Foggy in Daredevil: Born Again?
The eighth episode of Daredevil: Born heavily indicates that Ayelet Zurer’s Vanessa Fisk was the one who employs Dex to kill Foggy.
Dex, now in prison, appears for the first time in this episode since the pilot. In the opening scene, Dex is moved to the general population, which was likely orchestrated by Vincent D’Onofrio as Wilson Fisk / Kingpin, now the Mayor of New York City. As he is a former FBI agent, that is effectively a death sentence. Upon learning this, Matt looks into Foggy’s death. He goes for a drink at Josie’s, closed to the public since Foggy died in front of the establishment.
Matt learns that Foggy was drinking the expensive brand of scotch that they pick whenever they have won a case. He starts to realize that Foggy was celebrating early and that Dex didn’t target Foggy due to his old grudge against Matt but because he was hired to do so.
At first, Matt understandably concludes that Fisk ordered the hit. However, while attending a Black and White Ball hosted by Fisk and Venessa, Matt overhears Arty Froushan’s Buck Cashman warning the couple that Dex has escaped from prison. This is when Vanessa says that she has something to tell Fisk, and Matt immediately figures out that she is behind Foggy’s death. After all, at the time, Fisk was in prison, and Venessa was running the operations in his stead.
Vanessa likely ordered Foggy’s assassination because she blamed Matt and Foggy for what happened to her marriage and Fisk’s criminal empire. Matt put Fisk behind bars, with Foggy playing an integral role in it. Even after Fisk’s release, things weren’t the same between him and Vanessa, and the latter’s businesses continued to fall apart. Moreover, Foggy’s client was going to turn in evidence against Vanessa. So, Vanessa sought to eliminate Foggy.