A Large organised body of armed personnel trained for war.

A place or state of punishment of the wicked after death.

 Satan (the old man) according to Romans 6:5 ,who was a great imitator  from the beginning, who has set his armies as the holy angels. This his armies are being identified in the book of Ephesians, which says "For we do not fight against flesh and blood, but against principalities, against powers, against the rulers of darkness of this age, and the against spiritual host of wicked in the heavenly place" Ephesians 6:12.

  The following are the armies of hell;
  Principalities are the top-ranked demonic beings or creature, which is created by Satan. The word
principalities is known as ARCHE in Greek, which means "chief or master". They are chiefs or masters among demon, which is controlled by Satan. Principality is the spirit which assigns or controls other demonic spirits to operate in the disobedient people. This demons are subject to Christ (Ephesians 1:20-22) and they do not have power over the spirit filled believers as it is written in Ephesians 2:6.

  The "powers" is the next rank after the principalities, which are the officers of darkness. Power is traced to the Greek word "Exousia" which is understood as "delegated authority". Just like that of the policeman. The demons operate in way that it is not seen naturally using your eye. And this powers can not seperate us from the love of God (Romans 8:38).
 These powers will be destroyed by the wrath of God at the end of the age.

  This the next in the army of hell. Rulers of the darkness are the spirit that seize and takes hold of the darkness and evil doings. It can be traced to a Greek word called "Kosmokrator" which means "To seize and take hold of governments of the sake of darkness and evils". These powers of rulers of the darkness tries to take over the offices of government, legislature and even the court.

  The spiritual forces of wickedness are the unclean spirit, which we are fighting with on daily basis. The word "DEMON" means "Torment the mind". This lower level spirit are the ones we deal with on daily basis. The armies of Satan are well organised in such a way that they keep on trying to take you away from God.

 So therefore, "Take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand. Stand therefore, having girded your waist with truth, having put on the breastplate of righteousness, and having shod your feet with the preparation of the gospel of peace; above all, taking the shield of faith with which you will be able to quench all the fiery darts of the wicked one. And take the helmet of salvation, and the sword of the spirit, which is the word of God; praying always with all prayer and supplication in the spirit, being watchful to this end with all perseverance and supplication for all the saints-- Ephesians 6:13-18.