Board Thread:General MK Discussion/@comment-30711175-20180507212443/@comment-30711175-20180508132337

I see what you're both saying. Before it's development Ed Boon was working on making a "Mortal Kombat 8" (the basis of what would later become Mortal Kombat 2011) until a deal was made with Warner Brothers to develop Mortal Kombat vs DC Universe.

https://www.engadget.com/2007/02/05/mortal-kombat-8-inspired-by-gears-of-war-using-unreal-engine-3/

In effect MKvsDCU became the eighth game, because many fans wanted it to be, given it's break from the three fighting style 3D gameplay of previous entries, and it's depiction of characters in their prime, like a living Liu Kang and a Raiden that hadn't been corrupted.

Although I still find it odd to consider a non-canonical game in the Mortal Kombat franchise a principal entry rather than just a spin-off or crossover. I guess that was a mistake on the part of Ed Boon when he decided to call the reboot to his franchise the "ninth" game, and stick to that numbering system with it's sequel, Mortal Kombat X.