"Christian" and "serial killer" are mutually exclusive. You would be one or the other not both, at the same time.
Revelation 21:7-8
(7) He that overcometh shall inherit all things; and I will be his God, and he shall be my son.
(8) But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death.
Job seems to think sins are forgiven when you die: (as in the price of sin is death)
Job:14:14-14:
If a man die,
shall he live again?
all the days of my appointed time will I wait,
till my change come.
Thou shalt call,
and I will answer thee:
thou wilt have a desire to the work of thine hands.
For now thou numberest my steps:
dost thou not watch over my sin?
My transgression is sealed up in a bag,
and thou sewest up mine iniquity.
Great tribulation in prophecy is about hell, the ones in these verse were sent to hell for their sins, this is them after the GWT event and just before they are given the living water when they enter New Jerusalem for the ride back to this earth as the 1st event in the new earth era.
Re:7:9-17:
After this I beheld,
and,
lo,
a great multitude,
which no man could number,
of all nations,
and kindreds,
and people,
and tongues,
stood before the throne,
and before the Lamb,
clothed with white robes,
and palms in their hands;
And cried with a loud voice,
saying,
Salvation to our God which sitteth upon the throne,
and unto the Lamb.
And all the angels stood round about the throne,
and about the elders and the four beasts,
and fell before the throne on their faces,
and worshipped God,
Saying,
Amen:
Blessing,
and glory,
and wisdom,
and thanksgiving,
and honour,
and power,
and might, be unto our God for ever and ever.
Amen.
And one of the elders answered,
saying unto me,
What are these which are arrayed in white robes?
and whence came they?
And I said unto him,
Sir,
thou knowest.
And he said to me,
These are they which came out of great tribulation,
and have washed their robes,
and made them white in the blood of the Lamb.
Therefore are they before the throne of God,
and serve him day and night in his temple:
and he that sitteth on the throne shall dwell among them.
They shall hunger no more,
neither thirst any more;
neither shall the sun light on them,
nor any heat.
For the Lamb which is in the midst of the throne shall feed them,
and shall lead them unto living fountains of waters:
and God shall wipe away all tears from their eyes.
Re:19:21:
And the remnant were slain with the sword of him that sat upon the horse,
which sword proceeded out of his mouth:
and all the fowls were filled with their flesh.
Isa:65:12-16:
Therefore will I number you to the sword,
and ye shall all bow down to the slaughter:
because when I called,
ye did not answer;
when I spake,
ye did not hear;
but did evil before mine eyes,
and did choose that wherein I delighted not.
Therefore thus saith the Lord GOD,
Behold,
my servants shall eat,
but ye shall be hungry:
behold,
my servants shall drink,
but ye shall be thirsty:
behold,
my servants shall rejoice,
but ye shall be ashamed:
Behold,
my servants shall sing for joy of heart,
but ye shall cry for sorrow of heart,
and shall howl for vexation of spirit.
And ye shall leave your name for a curse unto my chosen:
for the Lord GOD shall slay thee,
and call his servants by another name:
That he who blesseth himself in the earth shall bless himself in the God of truth;
and he that sweareth in the earth shall swear by the God of truth;
because the former troubles are forgotten,
and because they are hid from mine eyes.
When your sins are not remembered, does God then send you to the fiery lake like some people alive today believe? Or do they complete what the new earth verses promote as the 'servants' will be in Jerusalem, New Jerusalem to be exact as that Jerusalem is also part of the new earth.
The new earth as defined by the many visions Enoch was shown, that makes it the whole universe as it is empty of angels who have moved to their permanent heaven, Mount Sion in Hebrews:12.