The team changed it to red in order to avoid any confusion
David Jaffe, the game developer who created the God of War series, reveals that the first design for the character of Kratos used blue warpaint and was pretty similar to the Barbarian that Blizzard was creating at the same time for Diablo 2.Nobody in the Sony Santa Monica development team noticed the similarities until an outside source pointed them out and so, they chose to turn the warpaint red in order to make sure that gamers did not confuse the two characters.
David Jaffe is currently has a collaboration with thatgamecompany.
At the moment, Sony Santa Monica is working on a new God of War video game, called Ascension, which will be launched during March 2013 only on the PlayStation 3.
The story is a prequel and the game will offer multiplayer for the first time in the series.