Details: One of the ten possible challengers you will face as you sit on the Champion's Chair in the Champion's Hall after defeating the Elite Four is Gladion. After assisting him in finding his own path and purifying the Aether Corporation, he has defeated the Elite Four to Battle you once again. His team still doesn't specialize in any given type, but his Silvally remains super effective against your starter.
Challenger Gladion (Rowlet Starter) - Level 63 Crobat, Level 63 Weavile, Level 63 Porygon-Z, Level 63 Lucario w/Steelium Z, Level 63 Silvally w/Fire Memory
Challenger Gladion (Litten Starter) - Level 63 Crobat, Level 63 Weavile, Level 63 Porygon-Z, Level 63 Lucario w/Steelium Z, Level 63 Silvally w/Water Memory
Challenger Gladion (Popplio Starter) - Level 63 Crobat, Level 63 Weavile, Level 63 Porygon-Z, Level 63 Lucario w/Steelium Z, Level 63 Silvally w/Grass Memory