After these two destructive attacks, 1/3 of the alligators were already dead and most of the others were wounded which balanced the fight a little.
And of the 2/3 of the alligators that remained, Roman killed half of them all by himself to prevent the boys from feeling overwhelmed by the number that remained.
Cassy's flames under Blaze's command mainly protected the boys by deflecting spells or drawing the attention of the alligators on them.
Because as Cassy didn't earn experience points by killing magic beasts, she preferred to instead let the boys earn as many experience points as possible by letting them kill these magic beasts.
And her father did exactly the same as she did, Roman's flames joined his to kill the elephants and rhinoceros and so Yellow who was in charge of dealing with these magic beasts always made sure that it was Roman's flames that gave the final blow.