To defeat Kory, it is recommended that the player tackles it with either very strong and tanky cats such as Jamiera Cat and Island Cat or with powerful midrangers that also double as the only meatshields, thus preventing Kory from landing hits (Cameraman Cat is a good example). Bahamut Cat will not help much as he is easily knocked back (except for A bahamut and it depends on the peons in the stage); however, with luck, Bahamut might land a hit and severely damage Kory. Decent ranged attackers such as Dragon Cat and Paris Cat also help, especially when stacked.
Spamming weaker cats will not work because they will be killed in the process simultaneously by the Shockwaves that also kill your attacking cats faster. Tanky but weak attacking cats (Sushi Cat, Tank Cat) will be a burden as they only make Kory create more Shockwaves, killing your other cats behind them. Octopus Cat is an obvious exception since it cancels Kory's waves.