The underworld, Satan’s Kingdom does exist.  It is found in our world
and even within our hearts!  Jer17:9. His Kingdom is earth-bound, rooted in the sensual, and appeals to our carnality – our flesh appetites and it also captivates our intellect that stirs
up pride in life.  1John 2:16.  In this place, you will find every wicked demon freely roaming
going about the business of their master the devil.  Revelation18:1-3.
 The power in this Kingdom is Sin and is the force, inspiration, and
nature of all business that is conducted, the chief Steward being Satan
himself.  To serve him are a vast host of demons who bow to his every
order.  They are each filled with hell’s fury knowing that their time is
running short and they have yet so much to do.  They each are specifically
trained and skilled in the tasks they are sent to engage in, they are counted
as superior in the field they work for they all have had since the beginning of
time to learn their trade. The doorway of unforgiveness has been one that has
yielded them great successes. They laugh and hope that these poor humans never
understand how detrimental it is when they do not forgive others!   Matt
18:21-35. 

The underworld thrives greater than that of the day before for the love of
many is growing cold and people are becoming haters of what is good and
despisers of God.  2Timothy 3:1-9.  Even for the godliest of soul Satan sends his Special Forces
to snare them into his lair.  His success depends upon how true they are
to who they say they believe.  For many in this group are greatly devoted
to the things of God, but some do not make Him Lord of their life or lover of their
soul.  These ones rely on what they know about Jesus Christ and
God rather than getting to know who they are and more still They
to know him.  And Satan dispatches his legion to make sure they do not
seek to personally connect with the living God, by making sure they are filled
with a lot of head knowledge, insights and good works.  They make sure
they are surrounded by the truth, but keep them away from setting out to know
the truth for themselves in relationship. 

Then there is another group that Satan despises to the core!  Though
they be a very small group they are devoted to God and keepers of His Flame as
the Spirit of God dwells in them burning with His white light.  Because
this people believe and trust in Jesus Christ, they make it their life’s work
to follow Him in all He has instructed them.  Only a select group of
Satan’s host attempts to contend directly with this crowd!   So, the
usual course of action that the satanic kingdom does for these ones is to
attempt to distract them through outside sources.  The evil ones look to
how they may get these devoted followers attention off of their God and will
use any and all they can to do so, using those who are close to them, such as their
spouses, children and close friends.  They will also attempt to sink these souls using
the cares (and worries) of life by having them look at the natural realm as
what they are to live by – and not according to the things of God and His
Spirit.  They know they must act quick, for in their experience they have
learned that this group looks out for one another, and are often supported in trials
with their brother and sisters gathering around and praying  – lifting up the name of Jesus on behalf of
the one in need.  In these cases, next thing you know, the one in
whom they have invested much time in targeting, comes to their senses and
confesses to the Lord in humility – and its game over at this point, because
they know once anyone humbles themselves before God and admits their wrong, all
they have done, is undone in a spit second. Once this happens they know what
comes next and so they hasten to flee as they hear them praising their God and
worshiping Him for His goodness!  This
kind of noise pollution has broken many of their ears as they were subject to it.
 It is clear that this one has made right
their path, looking once again with unwavering eye upon their God -they have no
choice but to flee from such a God glorifying presence!  James4:7. 
You see, the underworld hates prayer and worship that is offered to God in
Spirit and in truth.  John4:23-24. 
For the prayers of the Saints of God are effective in reaching Heaven’s supply. 
Satan sends out a specialized army to stop such prayers.  He employs many
avenues and tactics to bring results, for it is because of these prayers that
many of his great plans have been thwarted and overturned and is his aim to
bring any down any who are ones who are able to reach the throne of God in
prayer.  For these ones are the ones who cast mountains into the
sea!  It is through their prayers that lives (2Cor
10:4-6) are brought down and where the Spirit of the Living God sends forth
His Word to accomplish what He wills in bringing the revelation of Jesus Christ
His Son upon souls who are dying to know.  Isaiah55:11
  

May we understand truly that we fight not against flesh and blood but
against the underworld’s army and be counted as victorious in our tour of duty!

For we do not wrestle against flesh
and blood, but against principalities, against powers, against the rulers of
the darkness of this age, against spiritual hosts of wickedness in the
heavenly places.
Ephesians 6:12

Confess your trespasses to one another, and pray for one another,
that you may be healed. The effective, fervent prayer of a righteous man avails
much.  James 5:16