So, if one backslides from Christ and dies separated from Christ then that person is replaced by Christ?
Your questions are irreverent and you are not inspired by God with your human questions.
Below the Scriptures are inspired about the fate of judas that contradicts your opinion on the matter.
Nowhere in scripture does it say that Judas was saved or possessed eternal life. In fact it declares just the opposite. The bible teaches that Judas was the son of perdition from the beginning. He was created for the very purpose and role as the traitor who would betray Jesus. Jesus said of Judas it would of been better off for him to not even been born than to betray the Son of Man.
John 6:63-65
The words I have spoken to you are spirit and they are life. 64 Yet there are some of you who do not believe." For
Jesus had known from the beginning which of them did not believe and who would betray Him. 65 He went on to say, "This is why I told you that no one can come to me unless the Father has enabled him."
John 6:70-71
Then Jesus replied, "Have I not chosen you, the Twelve?
Yet one of you is a devil!" 71 (He meant Judas, the son of Simon Iscariot, who, though one of the Twelve,
was later to betray Him.)
John 12:4-6
But one of his disciples, Judas Iscariot,
who was later to betray Him, objected, 5 "Why wasn't this perfume sold and the money given to the poor? It was worth a year's wages." 6
He did not say this because he cared about the poor but because he was a thief; as keeper of the money bag, he used to help himself to what was put into it.
John 13:10-11
10 Jesus answered, "A person who has had a bath needs only to wash his feet; his whole body is clean. And you are clean,
though not every one of you." 11 For
He knew who was going to betray Him, and that was why He said not every one was clean.
John 17:12
12 While I was with them, I protected them and kept them safe by that name you gave me. None has been lost except
the one doomed to destruction so that Scripture would be fulfilled.
The same word is used to describe the very man of sin, the antichrist in:
2 Thessalonians 2:13-
Don’t let anyone deceive you in any way, for that day will not come until the rebellion occurs and the man of lawlessness is revealed,
the man doomed to destruction.
STRONGS NT 684: ἀπώλεια
ἀπώλεια, ἀπωλείας, ἡ (from ἀπόλλυμι, which see);
1. actively, a destroying, utter destruction: as, of vessels,
Romans 9:22; τοῦ μύρου, waste,
Mark 14:4 (in
Matthew 26:8 without a genitive) (in Polybius 6, 59, 5 consumption, opposed to τήρησις); the putting of a man to death,
Acts 25:16 Rec.; by metonymy, a destructive thing or opinion: in plural
2 Peter 2:2 Rec.; but the correct reading ἀσελγείαις was long ago adopted here.
2. passively, a perishing, ruin, destruction;
a. in general: τό ἀργύριον σου σύν σοι εἴη εἰς ἀπώλειαν, let thy money perish with thee,
Acts 8:20; βυρθίζειν τινα εἰς ὄλεθρον καί ἀπώλειαν, with the included idea of misery,
1 Timothy 6:9; αἱρέσεις ἀπωλείας destructive opinions,
2 Peter 2:1; ἐπάγειν ἑαυτοῖς ἀπώλειαν, ibid. cf.
2 Peter 2:3.
b.
in particular, the destruction which consists in the loss of eternal life, eternal misery, perdition, the lot of those excluded from the kingdom of God:
Revelation 17:8, 11, cf.
Revelation 19:20;
Philippians 3:19;
2 Peter 3:16; opposed to ἡ περιποίησις τῆς ψυχῆς,
Hebrews 10:39; to ἡ ζωή,
Matthew 7:13; to σωτηρία,
Philippians 1:28. ὁ υἱός τῆς ἀπωλείας, a man doomed to eternal misery (a Hebraism, see υἱός, 2):
2 Thessalonians 2:3 (of Antichrist);
John 17:12 (
of Judas, the traitor); ἡμέρα κρίσεως καί ἀπωλείας τῶν ἀσεβῶν,
2 Peter 3:7. (In secular authors from Polybius as above (but see Aristotle, probl. 17, 3, 2, vol. ii., p. 916{a}, 26; 29, 14, 10 ibid. 952^b, 26; Nicom. eth. 4, 1 ibid. 1120{a}, 2, etc.); often in the Sept. and O. T. Apocrypha.)
Matt 26:23-25
23 Jesus replied, "The one who has dipped his hand into the bowl with me will betray me. 24 The Son of Man will go just as it is written about him.
But woe to that man who betrays the Son of Man! It would be better for him if he had not been born."
25
Then Judas, the one who would betray him, said, "Surely not I, Rabbi?"
Jesus answered, "Yes, it is you."
Acts 1:16-19
16 and said, "Brothers,
the Scripture had to be fulfilled which the Holy Spirit spoke long ago through the mouth of David concerning Judas, who served as guide for those who arrested Jesus— 17 he was one of our number and shared in this ministry."
18 (With
the reward he got for his wickedness, Judas bought a field; there he fell headlong, his body burst open and all his intestines spilled out. 19 Everyone in Jerusalem heard about this, so they called that field in their language Akeldama, that is, Field of Blood.)
Acts 1:24-26
Show us which of these two you have chosen 25 to take over this apostolic ministry, which Judas left to go where he belongs." 26 Then they cast lots, and the lot fell to Matthias; so he was added to the eleven apostles.
Ps 109:4-8
In return for my friendship they accuse me,
but I am a man of prayer.
5 They
repay me evil for good,
and hatred for my friendship.
6
Appoint an evil man to oppose him;
let
an accuser stand at his right hand.
7 When he is tried, let him be found guilty,
and
may his prayers condemn him.
8
May his days be few;
may another take his place of leadership.