WARNING: The following contains spoilers for Avengers #23, from Jason Aaron, Stefano Caselli, Jason Keith and VCs' Cory Petit, on sale now.
The Cosmic Ghost Rider/Frank Castle became an instant fan-favorite character after he made his debut in 2017's Thanos #13 by Donny Cates and Geoff Shaw. While he hailed from an alternate future timeline, it wasn't long before he eventually made the jump to the prime Marvel Universe. Recently, the character appeared in Cates and Shaw's Guardians of the Galaxy series. While he initially joined the team of cosmic heroes, he later betrayed them and sided with Eros and his Dark Guardians.
Then, in Guardians of the Galaxy #6, the Cosmic Ghost Rider died yet again, and he found his way to Hell, where he met the fiery realm's king, Johnny Blaze. Blaze challenged Castle to a demonic race, and that was the last we saw of the Cosmic Ghost Rider. That is, until now. In Avengers #23, Castle is back -- and he's ready to kill Earth's Mightiest Heroes.
The Cosmic Ghost Rider's return is tied directly to the events of the series' previous issue. In Avengers #22, Black Panther recruited the help of Hellstorm to perform an exorcism on Robbie Reyes' car. Unfortunately, the ritual didn't go as planned, and Robbie disappeared, taken down into the fiery pits of Hell. But as he left, something else came back out.
At first, the Avengers believe that the demonic presence slowly taking over the systems of the Avengers Mountain base is the demon that was inside Robbie's flaming car. But that isn't the case. The more Blade, Captain Marvel, She-Hulk and the rest of the team tangle with their invader, the more Hellstorm learns about him. He starts off by explaining that this is a demon he has never tangled with before, and that it isn't even from this time.
Finally, as the issue comes to a close, the scorching spirit takes on its true form and reveals itself to be, you guessed it, Frank Castle, aka the Cosmic Ghost Rider. But while we knew that the character would return, what is most surprising is the mission he reveals to be on: "I'm the guy who's here to murder the Avengers," he says. "I won't lie... This is gonna get messy."
We may not yet know why he is after the Avengers, but we can certainly take a guess. Considering Castle was last seen being challenged to a race by Blaze in Guardians of the Galaxy #6, it would appear as if the Cosmic Ghost Rider is now under the employ of the king of Hell. After all, Blaze is currently challenging another Ghost Rider, Robbie Reyes, to a race, in the hopes of taking his power to collect enough to prevent Mephisto from reclaiming his throne.
It's quite possible that Blaze knew the Avengers wouldn't leave one of their own behind, and that they would come search for him through Hell itself. Therefore, he may have sent the Cosmic Ghost Rider to stall them, to give him enough time to race Robbie before his teammates can come rescue him.
With the combined abilities of the Spirit of Vengeance and the Power Cosmic, Frank Castle is nearly unstoppable. Hopefully, the Avengers have enough firepower to stop him before he brings everything down.
Avengers #24 releases September 25.