The fifth Plague: please notice the key words - the seat of the beast; full of darkness; gnawed tongues for pain; blasphemed God; repent not.

Rev. 16:10-11 "And the fifth angel poured out his vial upon the seat of the beast; and his kingdom was full of darkness; and they gnawed their tongues for pain, And blasphemed the God of heaven because of their pains and their sores, and repented not of their deeds.

the fifth Trumpet: please notice the key words - the star fall from heaven(= the angel of the bottomless pit); darken the sun and air; desire to die but death flee from them; ten elements (of determined nature of the beast).

Rev. 9:1-11 Please read the text.

I see the parallelism between the fifth Plague and Trumpet;

1) the seat of the beast => the fallen star which is the angel of the bottomless pit (= the beast);
2) full of spiritual darkness => darken the sun and air by the reason of the smoke (Catholic system intercepts prayers of saints);
3) gnawed tongues for pain => seek death but flees from them (shall be tormented by refusing to be sealed of God);
4) repented not => ferocious descriptions of the ten elements of the fallen star(= the beast=Catholic).

The reformers risen out from Catholic through the Dark Ages in history. Their cry is "how long, O Lord, avenge our blood?" This is the fifth seal description. God told them to wait until
the number of martyrs are filled. Rev. 18:20 and 19:2 indicate when the time of God's recompense is.
Rev. 18:20 "Rejoice over her, thou heaven, and ye holy apostles and prophets; for God hath avenged you on her."
Rev. 19:2 "For true and righteous are his judgments: for he hath judged the great whore, which did corrupt the earth with her fornication, and
hath avenged the blood of his servants at her hand."

The fifth church of Sardis has the background of Reformation Period. Rev. 3:4 "Thou hast a few names even in Sardis which have not defiled their garments;
and they shall walk with me in white: for they are worthy."

There is a profound understanding in the method a linier perspective for interpreting Revelation of the four pillars.

The comparison of the four pillars, seven churches, seals, trumpets, and plagues in the fifth linear starkly reveals the presence of impending death.

The fifth church condition teeters on the edge of this grim reality. Rev. 3:1-2 "...I?know thy works, that thou hast a name that thou livest, and art dead. Be watchful, and strengthen the things which remain, that are ready to die: for I have not found thy works perfect before God.."

The fifth seal indicates that the martyrs are crying out from under the altar, seeking vengeance for their blood. Rev. 6:9-10 "...he souls of them that were slain for the word of God, and for the testimony which they held:?And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth?"

God inflicts the fifth plague on the Papacy, the seat of the beast that persecuted and killed reformers during the Middle Ages. Rev. 16:10-11 "And the fifth angel poured out his vial upon the seat of the beast; and his kingdom was full of darkness; and they gnawed their tongues for pain,
And blasphemed the God of heaven because of their pains and their sores, and repented not of their deeds."

The identity of the fallen star in the fifth trumpet is that of the angel of the bottomless pit where spiritual darkness resides. Rev. 9:1-11 "And the fifth angel sounded, and I saw a star fall from heaven?....the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue hath his name Apollyon."

In the fifth element of the four pillars, we discover the root cause of the issue and why God must punish the seat of the beast.