The reboot of "Hellboy" has been written by Andrew Cosby, Christopher Golden, Mike Mignola and Aron Coleite.
David Harbour stars as Hellboy who, along with his team of paranormal researchers, try to save the world from a medieval sorceress who wants to destroy humankind.
Mitchell will play the role of Ganeida, an elder witch who has decided that Nimue's wrath has gone on for too long and must be stopped, reported Deadline.
Skrein exited the reboot following public outcry against whitewashing in Hollywood, saying it was important to "honour ethnic minority stories and voices in arts".