Daredevil (Charlie Cox) and Echo (Alaqua Cox) are two of the most anticipated heroes of the Marvel Cinematic Universe's Phase 5. Their respective MCU series will hit screens in 2024 and promise another wild ride into Hell's Kitchen alongside Vincent D'Onofrio's Kingpin. While their respective MCU series are bound to have twists and turns, they have a more complicated relationship in the comics. Echo's first appearance is in a Daredevil comic, so it's not surprising that they also have a close connection in the MCU. Created by David Mack and Joe Quesada, Echo debuted in 1999's Daredevil #9 as Wilson Fisk's ward, which he manipulates to further his evil plans.
Source：https://www.cbr.com/daredevil-echo-relationship-inform-show/
