Issue #111 of game magazine, GamesTM, has an 8-page feature on the History of the Ys series. Parts of the original draft for the feature have been edited out of the magazine version, and the uncredited author, John Szczepaniak, has some of these available for reading on his blog, including brief quotes from the president of Falcom.
Here’s a brief snippet from the post, which you can check out at the link above if you’re interested in reading it:
JS: The popularity of the Ys series has endured for 24 years. Why do you feel this is? Are you planning a surprise for its 25th anniversary?
TK: In Ys lore Adol is said to have left hundreds of adventure journals. The latest adventure we released was the 7th adventure so there are a lot more adventures to cover. It might be the excitement of wondering what adventure Adol tackled at what age that makes this series possible.
There are also a few quotes from Ys fan-translator, Deuce, who’s licensed some of his work to Xseed for recent Ys releases, and with Ken Berry, Xseed’s director of publishing, about the partnership with both Falcom and Deuce.