Was it given because of the War for Cybertron game was being made or did the writer come up with it himself?
Does anyone one here know or have any ideas ?

 

The Transformers Animated: the AllSpark Almanac II came out in 2010 but spotlight Blurr came out in 2008.

 

Notice it says "1986" right before the g1 version.

 

The game started production in 2008, the same year the comic released, and his name was Sentinel Prime for most of the game development and tie-in materials before it got changed to Zeta for the final release of the game. So most likely
Shane McCarthy came up with Zeta Prime in Spotlight Blurr and his name was later reused by Hasbro/High Moon, rather than the other way around.

"The original cartoon version of Zeta Prime was never named in fiction. The character is referred to as New Narrator in the dialogue script for "Five Faces of Darkness, Part 4" and was not given the name "Zeta Prime" until The AllSpark Almanac II declared it so via an Ask Vector Prime entry." - from the wiki.

 

Why do you think they changed it for the game ?

 

No idea. No reason for the change was ever given.

 

I may have read somewhere that Transformers Autocracy was years in mind, so maybe it was Chris Metzen who came up with the name zeta prime and Shane McCarthy used it to connect the story’s together.