Board Thread:Episode Discussion/@comment-30505072-20180118160922/@comment-4241330-20180304015227

I'm sure the most likely reason the Guard doesn't appear in the events of "Simba's Pride" is because Rafiki tells them it is time to follow a new path. The series ends with Kion saying goodbye to his family and telling Kiara she'll make a great queen, as well as Timon and Pumbaa giving Bunga one last hug. Then they watch as the Guard walks off into the sunset.

...and then sometime afterwards there'd be a standalone special where they return to the Pridelands as adults.