Joseph had two sons, Manasseh and Ephraim, and they became two tribes. But as to Jesus’s human nature, he was a descendent of Judas tribe but not Manasseh tribe or Ephraim tribe. Why is it like that?
It is true the main characters in Genesis from chapter 12 to the end are Abraham, Isaac, Jacob and Joseph. They carry forth the history of the people of God, Israel. However, in chapter 49 Jacob blesses all his sons with quite different blessings and he ends up giving the blessing of the first born, to lead the family and continue family line to Judah.
Reuben is not blessed, because he defiled his father’s bed. (v3-4) Simeon and Levi are cursed because of their violence (see v5-7 and Gen 34:25 and 30). And Judah is the first to receive an actual blessing. He also proved himself when he gave his own life and family as ransom to guarantee that the youngest brother Benjamin will be safe on their trip to Egypt.
From that time on Judah was the first among his brothers. Later the other ten tribes, besides Judah and Benjamin, separate from the House of David and form their own northern kingdom of Israel. They disappear more and more from the central history of the people of God, which is now moving straight towards the birth of Jesus.
So here you can see that the blessing moved on differently than the the number of pages Joseph has in Genesis versus Judah.
That is Judah’s, not Judas. Just correcting a typo. 
The descendents of Judas have many Kings, Jesus is the King of all human. He should born from a family of King.
It is history. There is no if, no why. Jesus was born in tribe of Judah.
Judah is not the same as Judas. Is that the difference?