Satan means an accuser, and devil means a slanderer.

We're down near Hell (Gehenna), and mankind contains these qualities.

People looking to blame externally, don't become wiser from taking personal responsibility, and asking for forgiveness (repentance).

When people are wise enough they notice evils; yet many ignorant people follow darkness as if it is light.

If we could get everyone in the world to recognize their own darkness, and stop blaming externally, there would be hope that the accusative nature (satan) could be transformed into something useful; yet when people would rather look outside, then they won't ask for the forgiveness from God, as they don't see it is their fault.