I'll help you out on this one, okay?
Satan can't do anything God does not allow him to do.
Then there is the famous quote:
"The Lord giveth,
And the Lord taketh away.
Blessed be the Name of the Lord
I know this is very difficult for you to understand, but the fact is that God has every right and reason to do whatever He deems right to do, including cause death.
Don't you know that everything on this planet that has life in it must die?
If it were not so, how could there ever be an end to the suffering in this world, and the hope of bliss in the next?
But let's consider a particular case, just for the helluvit.
There is a cult living in Nevada (no offense to folks in Nevada, this is a hypothetical).
These people are very devoted to their belief in their god.
Every spring, at the new moon, all the girls who reached maturity that year must run naked through a particular grove. After they've had a bit of a head start, the single men are released to catch and rape as many as they can. This is done to insure that their animals will be fertile, and their crops will thrive.
But that isn't even the worst of it. Later that evening, after the young girls are all brought back, cleaned up, and dressed, all the babies that were born to last year's crop of girls are brought out. They'd be about three months old now. They are brought to the place where the huge statue of their god stands, and...
They are thrown alive into a fire to be sacrificed to the god.
Every man and woman involved in this cult defends this sacrifice with their lives. They are well armed and plan to fight off any attempt to breach their compound. They have no intention of stopping, and claim that they have the right to practice their religion as they choose. They compare these infants to late term abortions, and claim that they have every right to burn them in the fire.
Are they murderers? I'd say so.
Do they deserve the death penalty?
Some folks would agree that they should be executed, both for the rather violent rape of the young girls, as well as for the murder of these babies.
So...if God were to...I dunno, cause an earthquake, or maybe a flood (well, it's God...He could cause a flood in Nevada if He wanted to!), and wiped these folks out, would that be alright? Or, assuming that no legal recourse is available, should He just allow this to go on?
Suppose He tries to reach them...suppose He sends folks to warn them, and they tell them that God is about to send the U.S. government in to wipe them out, unless they knock it off? Should our National Guard go in there, guns blazing, and try to rescue as many infants and young girls as possible?
But when God does these things in the OT, He is a an evil tyrant.
Of course, if He sits tight and lets them go on, He's also a neglectful God.
Ummm...excuse me, but God doesn't owe you an explanation, anyhow.