I Regressed to My Ruined Family

I was born as the oldest of a renowned swordsman family and became stronger faster than anyone
Yet I could not stop the dragons a great disaster that had appeared on the continent
I closed my eyes in my final moments thinking everything was over
I really thought it was over
But when I opened my eyes I was back in the past
A past that was very different from the world I knew
What Is this really my body Why dont I have any mana
Where did the castle go Whys there only a wooden house left
What The dragons and humans made a nonaggression pact
A family that had fallen and was on the brink of ruin
A family whose writing of divination had vanished
And a body in which no mana could be found
Ill have to keep myself busy from now on
The great hero of a renowned swordsman family
He is back in the past in a parallel world