There is a very strange relationship between twins, like one soul split in two and placed in two bodies. Of course, the relationship between twins is not generally good. Often the first half of a sentence spoken by the elder brother will be followed by the second half of the sentence by the younger brother. However, with the exact same face and exactly the same behavior, won't it change? Perhaps, this subtle relationship will only change when both parties grow up. By then, everything will be different.
[Purely venting Raven. I want them to cross over. . . .