I don’t think anyone really cares about Devil Slayer, so why is this billed as Devil Slayer and “guest-starring The Defenders?” Seems like they should have just given the team the major billing.
In fact, it’s neither.
For the whole issue, Spidey is teamed up with a villain who is simply disguised as Devil-Slayer but really isn’t, and in the end Spider-Man has to free the Defenders from the villain’s trap. Along the way, Spidey gets poisoned and has to travel into Kull’s time to get the cure.