As clouds are as loudest rumble anyone ever heard happened then the biggest lightning anyone saw rushed towards the four of them and all the people try to keep them safe. Then Raven, Zatanna, and John supply even more magic power as the size of the lightning gets double. As light and sound were so bright and loud that some had ear bleeding while Kara don't seem to affect by it.
Or, do you want him to become the strongest and chill as ruler of his own planet, focusing only on his planet, making his life nd the citizens around him stronger while the lives of everyone else outside of his planet, fall into chaos.