Cain is a character recorded in the Bible, whose name means "get". Those who kill relatives are the ancestors of all evil people in the world. Cain, one of the first two sons born by human ancestors Adam and his wife Eve, is the elder brother. Because he hated his brother Abel's behavior, he killed Abel and was punished by God.

The main description of Cain in the Bible is as follows:
Genesis 4:1-24
One day the man (Adam) slept with his wife Eve, and Eve became pregnant and gave birth to Cain, He said: "The LORD gave me a man. Later, he gave birth to Abel, Cain's brother. Abel was a shepherd and Cain was a farmer. One day Cain took vegetables and grain from the land as an offering to the LORD, and Abel also offered the firstborn of his flock and the fat of his sheep. The LORD looked at Abel and his offering, but did not look at Cain and his offering. Cain was greatly angry and turned pale. The LORD said to Cain: "Why are you angry? Why have you changed your face? If you do well, will you not be accepted by God? If you do not do well, sin will fall at the door. It will adore you, but you will subdue it."
Cain spoke with his brother Abel. They were in the field. Cain got up and beat his brother Abel and killed him. The LORD said to Cain, "Where is your brother Abel?" He said, "I don't know! Am I my brother's keeper?". The LORD said, "What have you done? The voice of your brother's blood cried to me through the earth. The earth opened its mouth and took your brother's blood from your hand. You will be cursed from this land. When you plant the land, the land will no longer serve you, and you will drift away and float on the ground."
Cain said to the LORD, "My punishment is too heavy for me. Now you have driven me out of the land so that I cannot see you. I will wander on the ground, and anyone who meets me will kill me." The LORD said to him, "It will never happen. Anyone who kills Cain will be punished sevenfold.". Then the LORD set up a sign for Cain, so that no one would find him and kill him. So Cain turned his eyes away from the LORD and no longer saw the face of the LORD, and went to live in the land of Nod, east of Eden.
Cain slept with his wife, and she conceived and gave birth to Enoch. Cain built a city and called it Enoch after his son. Enoch became the father of Enah, and Enah became the father of Mihuari, and Mihuari became the father of Methusari, and Methusari became the father of Lamech.
Lamech took two wives, one named Adah and the other named Zerah. Ada begat Jabal, the father of those who lived in tents and herded livestock. The name of Jabal's brother was Jubal; Juba is the ancestor of all those who play the piano and flute. Zillah also gave birth to Tubal Cain, a craftsman who made all kinds of bronze and iron utensils; The sister of Tubal Cain is Namah.
Lamech said to his two wives, "Adah and Zillah, listen to my voice; Lamech's wife, listen to my voice: if a man hurts me, I will kill him; if a young man hurts me, I will kill him; if a man kills Cain, he will be avenged seven times; if a man kills Lamech, he will be avenged seventy times seven times!".
About 3:12
Do not be like Cain, who belongs to the evil one and killed his brother. Why did you kill him? Because his own behavior is evil, his brother's behavior is good.
The above scriptures in the Bible contain a description of Cain's behavior - Cain's behavior is evil; Among them, the scripture also points out that Cain's offering was not acceptable to God because of his bad behavior. Although the Bible does not record what Cain did before offering sacrifices to God, it records that Cain later "became very angry with God" because God did not accept the offering, and then he became jealous and hated his brother Abel, so that he killed his brother. When God asked Cain where Abel was, Cain "lied". After being exposed, Cain only felt that the punishment was too heavy and did not repent for his actions.
In this way, from the perspective of the Bible, Cain's character is evil. The fact that God does not accept Cain's offering does not imply that "God favors Abel". On the contrary, it reflects the righteousness of sacrifice (different from the bribery offering of "seeking benefits only" in superstition).
In the Bible, the representative scriptures that echo this view are as follows:
1 Samuel 15:22
Samuel said, "Is the LORD more pleased with burnt offerings and peace offerings than with people listening to his voice? Obedience is better than sacrifice; obedience is better than the fat of rams.
Psalm 51:17
The sacrifice that God wants is the spirit of sorrow. God, you will not despise a sad and contrite heart.
Proverbs 15:8
The sacrifice of the wicked is abhorrent to the LORD; The upright man prays and is pleased with him.
Isaiah 1:11-17
The LORD said: "What is the benefit of your many offerings to me? I have had enough of the burnt offerings of rams and the fat of fat animals. I am not pleased with the blood of bulls, lambs, and goats. When you come to see me, who will ask you for these things so that you will trample on my courtyard? Do not offer any more vain offerings. Perfume is an abomination to me; new moons and sabbaths, as well as the assembly that is called, are also my abomination; do evil, and keep strict I can't tolerate the meeting. I hate your new moon and festival, and I think it's troublesome; I am impatient when I bear the burden. When you raise your hands and pray, I will cover my eyes; Even if you pray too much, I won't listen. Your hands are full of killing blood. Wash and purify yourselves, and remove your evil deeds from my eyes. Stop doing evil, learn to do good, seek justice, rescue the oppressed, avenge the orphan, and plead for the widow. "
Romans 12:1
Therefore, brothers, I urge you with the mercy of God to offer your body as a living sacrifice. It is holy and pleasing to God. It is natural for you to serve like this. Do not follow the example of this world, but change your mind, so that you can test what is God's good, pure and pleasing will.

Adam: According to the Bible, as the first human being born in the world, he is the father of all mankind.
Mother - Eve: According to the Bible, the second human being born, born from Adam's rib, is the mother of all mankind.
Abel: one of Cain's brothers, the second son of Adam and Eve, was later killed by his brother. The name means "void".
Seth, the third son of Adam and Eve, is one of Cain's brothers. The name means "gift". The person God gave to compensate Adam and Eve was born instead of Abel.
Sister - Aclima: According to some religious traditions, she is one of the daughters of Adam and Eve, and also the wife of Abel. She is considered to be the most beautiful of Eve's first daughters. Her name means "beautiful". Cain is said to hate her. Abel has never been mentioned as having a wife in the orthodox Bible.
Wife and sister - Awan: According to the pseudocode Jubilee, one of the daughters of Adam and Eve is Cain's sister and wife. She was Seth's sister. After Seth was born, she married Cain. After she slept with her husband, she gave birth to her son Enoch (not the one God met). The name means "injustice". In the orthodox Bible, Cain's wife's name is not officially mentioned.
Sister - Azura: According to the pseudocode "Jubilee Book", she is one of the daughters of Adam and Eve, the sister and wife of Seth. The name means "constraint". In the orthodox Bible, this character does not appear.
Son - Enoch: (Enoch): The son of Cain, who was not the same person as Enoch who met God. After his birth, Cain named the first city after him.
wife
Cain's wife should be his sister. The Bible does not specify how many children Adam had, especially in the family tree of the Bible, which does not seem to mention women. But the Bible points out that Eve is the mother of all living beings, and all people are from Eve.
At the beginning of the creation of the world, human beings should be intermarriage. Even in the era of Abraham, Abraham's wife Sarai was his half-sister. So Cain's wife and Seth's wife should be their own sisters. The Hebrew word "wife" is ishshah
Of course, this is based on the conjecture of the Bible. There is no text in the Bible that clearly explains this problem. But the belief that God created other people besides Adam and Eve is obviously devoid of biblical basis and contrary to the Bible.
brothers and sisters
In Genesis 5:4, there is an overview of the lives of Adam and Eve: "After Adam begat Seth, he lived for 800 years and had children and daughters."
In the life of Adam and Eve, they had many children, boys and girls. In fact, the Jewish historian Joseph wrote: "According to the ancient tradition, the number of Adam's children is thirty-three sons and twenty-three daughters."
The Bible did not tell Adam and Eve how many children they had, but considering their longevity (Adam lived 930 years - Genesis 5:5), it was reasonable to argue that they had many children. Remember: they were told to "produce many and fill the whole earth" (Genesis 1:28).