Information Before Story

In the canon KHR we all know, Vongola Decimo is also known as Neo Vongola Primo.

"Tsuna" and "Giotto". They had the same appearance, same kindness, same power, And perhaps, in this parallel world,

The same identity.

HAHahahahah!!!

Just kidding! You actually believed that? But Tsuna does have a brother named Ieyasu.

I wonder why?