Paul Mescal as Lucius in "Gladiator II."Aidan Monaghan/Paramount PicturesPaul Mescal plays Lucius Verus in "Gladiator II."The film revealed in a trailer — and makes it clear in the movie — that Lucius is Maximus' son.In "Gladiator," Lucius is just a child — here's what you need to know about him.Warning: Spoilers ahead for "Gladiator II."In "Gladiator II," Paul Mescal's Lucius is a vengeful heir to the throne who's out for blood — but in the first "Gladiator" film, his character is just an innocent child who mucks up his parents' coup d'état."Gladiator II" picks up a few decades after Ridley Scott's 2000 film, which starred Russell Crowe and Joaquin Phoenix.