The color orange carried a unique subtext among the Defenders. Devil-Slayer and Gargoyle, the two Defenders with unmistakable amounts of orange in their appearance, both had origin stories tied to the occultand both were intent on battling demons.
Daimon Hellstrom, the begrudging Son of Satan, had similarly colored hair when he made his debut in Marvel Spotlight #12.
Although Hellstrom appeared blond in Marvel Spotlight #13-19, his hair color was consistently red (a.k.a. orange) from that point on, including his appearances with the Defenders.