Character / Hero cards came in a 3-stat or 4-stat version (Energy, Fighting, Strength, Intellect)
The 3-stat versions were produced in the first 3 series; Original, Powersurge, and Mission Control.
They were updated to include the intellect stat beginning with the DC expansion.
Later expansions updated each character from the first 3 series with a 4-stat version.
Below are a few pictures representing various character / hero cards.