It began when Jeska sealed the last major rift in Otaria in 4500 AR. It caused all remaining fractures to heal, first in Dominaria but then spreading throughout the Multiverse in a chain reaction. The Mending allowed mana to flow freely throughout Dominaria once more, returning life and hope to the dying world. All creatures which had appeared from the past during the Time Spiral crisis returned to their original time. With the last Time Rift closed, Dominaria's mana flowed back into the land instantaneously, and the world healed and rejuvenated quickly with that infusion of power.
After the Mending, the Multiverse found a new balance with the Planeswalker's spark, with far reaching consequences. Planeswalkers lost their immortality and godlike powers and much of their additional magic power. For example, they stopped being able to transport other people during a planeswalk. At the same time, all existing planar travel tech also stopped working. New tech was possible, but so far the only example seen is the Planar Bridge created by Rashmi on Kaladesh, which has notable limitations regarding organic matter.
- James Wyatt (2018), The Art of Magic: The Gathering - Dominaria. VIZ Media.
- Mark Rosewater (April 03, 2018). "Do these people still exist in current Dominaria or where they thrown back into the past with the mending?". Blogatog. Tumblr.
- Kelly Digges on Twitter
- Magic Story Podcast: The Mending (May 3, 2018)
- James Wyatt (January 25, 2017). "Puppets". magicthegathering.com. Wizards of the Coast.
- According to Doug Beyer in Magic Story Podcast -- Q&A May 24, 2017