
Sphinx of Uthuun | Art by Kekai Kotaki
See those little birds out there in the sky? They're there to show that Sphinx of Uthuun is bigger than them. The presence of tiny "scale birds" shows that the main creature is giant.

Gaea's Revenge | Art by Kekai Kotaki
Gaea's Revenge is so big that those birds probably just think it's a mountain or something.

Sun Titan | Art by Todd Lockwood
Without birds: a guy with a sword. With birds: a titan with a sword.

Primalcrux | Art by Wayne Reynolds
Technically, the art for Primalcrux has scale bats, not birds. But that's close enough, right? Wayne Reynolds is a master; he can do that.

Hedron Rover | Art by Jason Felix
That's actually not the original version of Hedron Rover. During development, the creature was a bit larger, so the first illustration looked like this:

Hedron Rover | Sketch by Jason Felix
See? Change the scale birds and you change the size of the creature!