"For me, a group with a "charismatic leader who has many claims and a promise that he alone can save me", is a cult. It is obvious."

Oh, I agree. It is very obvious. But only to people not inside the cult. To members of the cult, it isn't obvious, or they would leave. From the inside, it just seems like self-evident reality.

"We have seen many individuals who founded their own “groups/movements” based on their attempts to foretell the future of the world. It already happened in the past. It’s so sad to say, this is still happening today in many places."

Indeed. Jesus was one of those people, As were Muhammad and Joseph Smith. You will find in the Bible that Jesus does all of the things I listed that you identified as signs of a cult.

Many of those practices are no longer part of Christianity today, because of how cults change their policies as they mature into religions. The burdensome requirements to convert, like selling your possessions, are necessary early on to render converts dependent on the cult.

But such policies also make useful ammunition for critics. So they are jettisoned as membership grows to the point where it's no longer necessary to retain converts.

If you think hard about what a cult would look and behave like if it was extremely successful, with much of humanity as members, and lasted for thousands of years, you may have an epiphany.

In the mean time, some relevant verses:

Imminent end of the world:

1 John 2:18

Dear children, this is the last hour; and as you have heard that the antichrist is coming, even now many antichrists have come. This is how we know it is the last hour.

Matthew 16:27-28

For the Son of Man is going to come in the glory of His Father with His angels, and will then repay every man according to his deeds. Truly I say to you, there are some of those who are standing here who will not taste death until they see the Son of Man coming in His kingdom.

Matthew 24:34

Truly I tell you, this generation will certainly not pass away until all these things have happened.

Matthew 10:23

When you are persecuted in one place, flee to another. Truly I tell you, you will not finish going through the towns of Israel before the Son of Man comes.

Sell your belongings:

Luke 14:33

"In the same way, those of you who do not give up everything you have cannot be my disciples."

Matthew 19:21

Jesus answered, "If you want to be perfect, go, sell your possessions and give to the poor, and you will have treasure in heaven. Then come, follow me."

Luke 12:33

“Sell your possessions and give to the poor. Provide purses for yourselves that will not wear out, a treasure in heaven that will never fail, where no thief comes near and no moth destroys.”

Luke 18:22

When Jesus heard this, he said to him, "You still lack one thing. Sell everything you have and give to the poor, and you will have treasure in heaven. Then come, follow me."

Please note that only Luke 18:22 and Matthew 19:21 concern the story of Jesus advising the wealthy young man about the difficulty of entering heaven.

These verses are included for completeness, and to acknowledge the existence of this story because the most common objection I receive to the claim that Jesus required followers to sell their belongings is that I must be talking about this particular story and misunderstanding the message it conveys.

However in Luke 12:33 and Luke 14:33 Jesus is not speaking to that man but to a crowd following him, and in 14:33 he specifically says that those who do not give up everything they have cannot be his disciples. It is therefore not a recommendation but a requirement.

Cut off family members who try to stop you:

Luke 14:26

"If anyone comes to me and does not hate father and mother, wife and children, brothers and sisters--yes, even their own life--such a person cannot be my disciple."

Matt. 10:35-37

“For I have come to turn a man against his father a daughter against her mother a daughter-in-law against her mother-in-law---a man’s enemies will be the members of his own household. Anyone who loves their father or mother more than me is not worthy of me; anyone who loves their son or daughter more than me is not worthy of me.”

Matthew 19:29

And everyone who has left houses or brothers or sisters or father or mother or wife or children or fields for my sake will receive a hundred times as much and will inherit eternal life.

Do not apply critical thought to doctrine:

Proverbs 3:5

“Trust in the LORD with all your heart and lean not on your own understanding”

2 Corinthians 5:7

“For we live by faith, not by sight.”

Proverbs 14:12

“There is a way that appears to be right, but in the end it leads to death.”

Proverbs 28:26

“Those who trust in themselves are fools, but those who walk in wisdom are kept safe.”

Now, for another topic:

"If that “charismatic speaker who claims that the world is ending soon” according to his own calculations of days, then I can say that he is a false prophet."

It's interesting you should say that. Jesus did say that no man can know the day or the hour. But he said nothing of the year or century. It just meant the date could not be known with precision.

Jesus himself repeatedly predicted a general timeframe within which to expect his return. Every time he did this, it was within the lifetimes of his contemporaries, not thousands of years in the future:

Matthew 16:27-28:
"For the Son of Man is going to come in his Father’s glory with his angels, and then he will reward each person according to what they have done. Truly I tell you, some who are standing here will not taste death before they see the Son of Man coming in his kingdom.”

Christ predicted his second coming would occur very soon after his death. That never took place. Revelations was a metaphorical prediction of the fall of Rome, written as metaphor because Christians could not openly criticize Rome at the time for fear of persecution. Everywhere in the New Testament that Christ discusses his second coming, it is explicitly said to be imminent, not 2,000+ years later.

"…he was wrong. He clearly knew no more about the end of the world than anyone else. It is certainly the most embarrassing verse in the Bible."
—C. S. Lewis, The World’s Last Night and Other Essays (New York: Harcourt Brace & Company, 1973), 98. (Post-conversion)

Pre-emptive answers to common objections:

1. “No one knows the day or the hour” means that the date cannot be known precisely. However, that does not stop Jesus from repeatedly giving a general timeframe of several decades within which to expect his second coming.

2. It can't be interpreted to mean you and I as metaphorical apostles because he specifically says "some of you standing here", as in the people he was talking to at that time. The full context reinforces that, he was speaking to disciples who accompanied him to Caesar Phillipi who wanted to know how they would recognize the second coming.

3. It can't be interpreted as referring to the transfiguration because the events described in verse 27 don't happen at the transfiguration (Jesus, God and angels coming from the clouds, judging mankind according to their deeds).

4. Daniel's visions don't satisfy the claim either because while they depict seven apocalyptic creatures (representing kingdoms that ruled over the Jews up to that point) nowhere does Daniel's vision describe Christ's return.

5. The 666/616 gematria code known as the number of the Beast must mean Nero/Neron, because only that name fits both 666 (Nero) and 616 (Neron). Source: http://www.math.harvard.edu/~elkies/mp666.html. This is because the book of Revelations was intended to metaphorically describe the fall of Rome, in a time when Christians could not openly predict it.

6. It's true that some of the events Christ said must occur before his second coming have not yet occurred. However, submitting this as proof that Christ must have meant something else in the verses supplied above presupposes that he actually was clairvoyant, instead of simply being wrong about those predictions too, because he was a regular human being without the ability to see the future.

7. For those who say that no Christian tastes death but lives on forever, it is clear Christ meant bodily death by other verses wherein he tells his traveling companions which signs they may personally expect to witness as his second coming approaches. They, according to Christ, should anticipate those signs within their lifetimes and would know by those signs that his second coming was imminent. There are two deaths: bodily and spiritual.

8. Jesus’ resurrection does not fit the criteria supplied by the verse because he did not, on that occasion, “come in his Father’s glory with his angels, and reward each person according to what they have done.” By that description it’s clear he is referring to his second coming, as explored more thoroughly in Revelations.

9. “When Christ said some standing there would not taste death before witnessing his return, that isn’t the kind of death he meant.” But it is. Hence "taste". There are two deaths. The first bodily and the second spiritual. He's referring to the first (to merely taste, rather than to eat) as those saved in him will only briefly experience death before being resurrected.

10. He cannot have meant the destruction of Jerusalem because the events described (Christ coming in the clouds with God and angels, judging men according to what they had done) did not occur when Jerusalem fell.

11. “But Jesus performed miracles!” ….according to a book written by his devoted followers, used to convert more people to their religion. According to books written by Scientologists about L. Ron Hubbard, he was one of America's first nuclear physicists, a war hero and the greatest humanitarian ever to live. And the Qur'an says that Muhammad once split the moon in half by pointing at it, then rejoined the halves. Was Muhammad therefore a true prophet?

12. “How do you explain all those fulfilled prophecies?” Almost all of which are recorded in one book of the Bible, then recorded after the fact as having come true in a later book of the Bible. This is a very easy trick. Observe: In 1998 I predicted that on Sept. 11, 2001 planes would collide with the WTC towers. Amazing! How did I know that? Am I clairvoyant?

This is also how Qur’anic prophecies work, although I assume you’d already figured that out, just not applied it to your own religion. The ones not yet fulfilled are sufficiently vague as to always be true. Like “there will be wars and rumors of wars”. This is so the eschaton always appears imminent: World events will always appear to confirm Biblical prophecy, no matter what century you live in. The purpose being to supply a perpetual sense of urgency to drive evangelism.

The entirety of Matthew through John, wherever Christ speaks of his return he does it in language that makes it clear he expects it to be IMMINENT. A good example of this is in 1 John 2:18, where Christ urges the followers he is writing to: “18 Children, it is the last hour, and as you have heard that antichrist is coming, so now many antichrists have come. Therefore we know that it is the last hour.” also Matthew 10:23, "When you are persecuted in one place, flee to another. Truly I tell you, you will not finish going through the towns of Israel before the Son of Man comes."

Over and over he stresses to them that they should not to make long term plans (like marriage: 1 Cor. 7:29-31), not to go on living in the world as if it will still be here for the rest of their lives, and to look for specific signs that they specifically can expect to see shortly after his crucifixion.

This was committed to writing a few decades after Christ's death by people who still believed they were living in a window of time that was consistent with what Christ predicted for his return. Then it just never got changed, because of the freezing effect of orthodoxy on preserving the contents of a holy text. It was just continually reinterpreted in a way to make it seem like Jesus wasn't wrong.