Is Satan the ruler of this world?

...if you want to call it like that - yes. Dark forces drive humans to destroy the world - it will lead to a global suicide.
The solution would be love but love is almost gone from this world and the time is almost up to change the situation.

Satan does not exist except in the imagination of men.

He was, before Jesus Christ defeated death for us. Now, he's just a relatively powerless, homeless, vagabond spirit, prowling about the world, seeking the ruin of souls through evil associations, sinful structures, lies and temptation. Much like the late Saddam Hussein had to hide out in "spider holes" after he was defeated, in Iraq.

Yes! Read here: https://www.jw.org/finder?wtlocale=E&docid=2014327&srcid=share

1 John 5:19 provides the answer.

It would seem so, yes.

No, only the natural world exists.

No. Just other people. Governments. 

No, the super rich are the rulers and they were worse than Satan. 

Hmm. The bible says yes and it says no from what I have read.