Challenge Event is a recurring event in Kingdom Hearts Unchained χ / Union χ. Unlike other events, quests are gradually added throughout the event period.

Challenge Event #1

 

The first Challenge Event was available from September 19 to 25, 2016. It contained twenty quests, gradually added in sets of five, called Trials.

Trial #1 was available from the start of the event.

Trial #2 was added on September 20.

Trial #3 was added on September 22.

Trial #4 was added on September 24.

Challenge Event #2

 

The second Challenge Event was available from October 24 to 30, 2016. It contained sixteen quests, gradually added in sets of four.

The Beginner quests were available from the start of the event.

The Intermediate quests were added on October 25.

The Advanced quests were added on October 27.

The Legendary quests were added on October 29.

Challenge Event #3

 

The third Challenge Event was available from November 14 to 20, 2016. It contained twenty quests, gradually added in sets of five, called Trials.

Trial #1 was available from the start of the event.

Trial #2 was added on November 15.

Trial #3 was added on November 17.

Trial #4 was added on November 19.

Challenge Event #4

 

The fourth Challenge Event was available from February 6 to 12, 2016. It contained sixteen quests, gradually added in sets of four, with increasing difficulty.

The Beginner quests were available from the start of the event.

The Intermediate quests were added on February 7.

The Advanced quests were added on February 9.

The Legendary quests were added on February 11.