Suggestions by @harrypotter4ever

Peyton List

as Calypso in Heroes of Olympus

Score: -1

Madison Iseman

as Calypso in Heroes of Olympus

Score: -1

Dove Cameron

as Calypso in Heroes of Olympus

Score: -1

Olivia Holt

as Calypso in Heroes of Olympus

Score: -1

Nathan Kress

as Frank Zhang in Heroes of Olympus

Score: -1

Victoria Justice

as Piper McLean in Heroes of Olympus

Score: +1

Lucy Hale

as Reyna Avila Ramrez-Arellano in Heroes of Olympus

Score: -1

Alexander Ludwig

as Jason Grace in Heroes of Olympus

Score: -1

Jake T. Austin

as Leo Valdez in Heroes of Olympus

Score: -1

Emily Skinner

as Annabeth Chase in Heroes of Olympus

Score: -1

Ryan Reynolds

as Poseidon in Heroes of Olympus

Score: +1

Oscar Isaac

as Hades in Heroes of Olympus

Score: +1

Jason Isaacs

as Hades in Heroes of Olympus

Score: +1

Ben Affleck

as Hades in Heroes of Olympus

Score: +1

Gary Oldman

as Hades in Heroes of Olympus

Score: +2

Mads Mikkelsen

as Hades in Heroes of Olympus

Score: +1

Luke Evans

as Hades in Heroes of Olympus

Score: +1

Ralph Fiennes

as Hades in Heroes of Olympus

Score: +1

Steve Coogan

as Hades in Heroes of Olympus

Score: +1

Jude Law

as Zeus in Heroes of Olympus

Score: +2