Now I have been thinking about it lately it makes sense let me explain,
1)In the 1st chapter Kawaki did said it's the end of shinobi just think about it maybe Shinobi has caused something bad into the future which led to destruction and to stop it some of the surviving people went back to past to remove the theory of Shinobi.
2) Momoshiki said clearly to Boruto that his blue eyes will take everything from him what if Boruto actually is the one who cause destruction in future and to stop that Jigen adopted Kawaki to have a match for Boruto in future.
3)Kara's technology is better than current shinobi world which led me to believe that they could be from future.
These are just some thoughts what do you think about it.
1)In the 1st chapter Kawaki did said it's the end of shinobi just think about it maybe Shinobi has caused something bad into the future which led to destruction and to stop it some of the surviving people went back to past to remove the theory of Shinobi.
2) Momoshiki said clearly to Boruto that his blue eyes will take everything from him what if Boruto actually is the one who cause destruction in future and to stop that Jigen adopted Kawaki to have a match for Boruto in future.
3)Kara's technology is better than current shinobi world which led me to believe that they could be from future.
These are just some thoughts what do you think about it.