Krishna said He is the father of Universe. But He starts war to kill Kowravas. Is it the father's dharma?

Kowravas also are his sons as He is the father of Universe. Why He should wait and see them becoming wicked, and killing them in war? If He is Almighty, He can very well change their mind and convert them good people. If Krishna has a Boss, wouldn't he put Krishna in hell for this crime?