Deathstroke made an appearance at the end of the Justice League movie. Lex Luthor wanted to form a league of his own to fight against Superman, Batman, Wonder Woman, Flash and Cyborg. Joe Mangiello played the part. Joe is famous for his roles in HBO show True Blood and Magic Mike movies.
Deathstroke was also going to be a villain in the new Batman movie. However, WB got a new director for the movie, now the Deathstroke appearance is uncertain.
WB also planning to do Deathstroke movie with Gareth Evans writing and directing the movie. Now that seems to got scrapped. Now we are hearing that Deathstroke might be in the Suicide Squad 2 movie, production starts this summer.
Deathstroke first appeared in DC Comics The New Teen Titans #2 (December 1980) written by Marv Wolfman and drawn by George Perez. Deathstroke, Slade Joseph Wilson, has great hand-to-hand combat, healing abilities, and great swordsman.
He started out as a main villain to Teen Titans, especially Dick Grayson (Nightwing) but throughout the years, also as a villain to Batman and Green Arrow.
A recent copy of The New Teen Titans #2 CGC 9.8 sold for $748.95.