"God is the greatest!"......?

Just now, my nephew screamed at me:
"God is the greatest!"
I just answered her:
"Is it?"

Is it the God is the greatest?
Is Him/Her being?
How about He/She just one of us?
Will He/She faces the failure?
Will He/She cries?
Will He/She......?
I confused of the God's presence.
If He/She being or the greatest,
why the disaster keep happen?
Why the worst person still being?
Why and why?

Hikari:
"The place with must has the shadow,
the lighter the place,
the darker the shadow."
Every event must has opposite effect.
The greatest God here,
there will be the worst evil.

The justice?
Depend on yourself.
Is that God being?
I don't know.