User blog comment:The Benyas/Dialga and Palkia/@comment-32948071-20180109201045

In Zeta, you catch Dialga by first deafeating Cyrus in the Challenge Championship to obtain secret password, then you use Tesseract on a pond, enter the secret password, and voila! If you sucessfully catch it, then talk to King Suzerain back at the Challenge Championship with Dialga in your party, he will give you Palkia.