Kill his team faster and he builds it slower.
Dont kill his team and you are done for.
Kylo teams are typically made up of aoe crit dealers or turn meter swap characters or both. Throw in a taunter like kru and you have a solid team.
But its not unbeatable and it doesnt always beat glrey. Timing is ecerything in kylo vs rey fights from the kylo side.
Rey teams are designed to force kylo in directions that dont help him build the ultimate faster. And its all about having at least 1 charge to use when rey does her ultimate..... which can be a challenge if your kylo is faster than opponents rey.