He was portrayed by Luke Treadaway.
Clash of the Titans (2010 movie)
Prokopion is a citizen of Argos and a fervent worshipper of the gods. When the war between the gods and men started, he continues to pray the gods and constantly tries to convince the other citizens to do the same. After some soldiers destroyed a statue of Zeus, Prokopion encounters them on the way to the palace of King Cepheus and warns them that the gods will punish them for their affronts, but they roughly push him.
Later that day, Hades appears in the palace and threatens to send the Kraken to attack Argos in ten days, unless they sacrifice the princess Andromeda. Shortly after, Prokopion attends the departure of a group of soldiers tasked by Cepheus to go see the Stygian Witches to find a way to kill the Kraken.
During the following days, Prokopion founds the Cult of Hades and manages to rally many citizens of Argos. One day, Andromeda secretly goes to hand out food to the poor people in the city, but she sees Prokopion making a speech to a crowd to convince them that they must pray Hades and sacrifice the princess. He then burns his own arm and is acclaimed by the crowd.
When the final day arrives, Prokopion leads the other cult members to the palace and they overwhelm the guards before capturing Andromeda. They forcibly take her to their temple and they tie her up to be sacrificed while Prokopion implores Hades. Soon after, they see the Kraken coming and starting to ravage the city, however the demigod Perseus arrives on the back of Pegasus with Medusa's head and is attacked by the Harpies of Hades. Perseus eventually falls in the temple and is attacked by Prokopion and some other cult members, but he manages to repel them and uses the head to turn the Kraken into stone. Then, Prokopion tries to attack Perseus with a spear, but Cepheus arrives and stops him by grabbing his burned arm. Prokopion uses his spear to stab him, however, one of the Kraken's petrified hands falls on them, killing them both.