Ken Sugimori, Game Freak’s character art director has admitted that he ran into problems when designing both legendaries for Pokemon X and Y. In an interview with Famitsu, he explains how he had to get help from his fellow art designer Yasuke Ohmura in order to finish the designs.
“I was tasked with designing both Xerneas and Yveltal, and I ran into a total wall in the process. So I gave the task over to [fellow art designer Yusuke] Ohmura for a while, and once he made some headway on it, I took it back over to finish it off. So they were a team effort. I’ve designed a lot of the legendary Pokemon over the years, but for whatever reason, it was really hard to come up with the concepts this time around. This was the first time I had to field someone else to get me out of my artist’s block, so in that respect, those are definitely the two Pokemon that stick out the most in my mind for this project.”