........Substitute Soul Reaper
That's him. My son. He's getting big...but there's more to Ichigo than you've seen. Sure, we've revealed to you that I, Isshin Kurosaki, am a soul reaper myself, but you don't know the half of it.
Everything began when I went on a special mission to the world of the living.
Let's start from the beginning.
/Isshin's Past/
A young soul reaper-in-training stood in line to recieve his shihaksho, the soul reaper's uniform. His boxy face and cropped black hair made him look older, but Isshin Kurosaki was no older than the son he would one day watch replace him as the family's resident warrior.
"Isshin Kurosaki. 5623rd class of the Spiritual Arts Academy. Top Student. You have been placed in the 12th seat of the 4th squad. Your kido abilities make you adequate for healing in the field and you will go through the ranks quickly. Congradulations, graduate."
ISSHIN'S POV
That's me, Isshin Kurosaki, graduating from the SAA in Soul Society. My entry into the 4th squad made my future ability as a doctor work out smoothly. My captain, Retsu Unohana, was a wonderful woman and a great captain to work under. She had held the squad together for over a thousand years, one of the few original captains to graduate from the academy built just before she became a soul reaper. I rose very fast, eventually making it to vice captain of her squad before being promoted to captain of squad 3. I held the position for over 20 years...then she came...
Masaki Uriashi was my biggest crush. She was the 6th seat of my squad and she was good at what she did. I soon promoted her to vice captain and she stayed by my side. We spent long days together and helped each other out in battle while other captains began to hold their lieutenants seemingly hostage, the memories of former 5th squad captain Shinji Hirako and his own lieutenant's strained relationship that quickly let to the death of the captain still there.
I finally got up the courage to ask her out after a major mission one day after 5 years together. She agreed and thus our relationship was born. However, a conspiracy within the guard exiled her to the world of the living...but I could not follow. I was a captain and thus was needed to hold everything together.
Grief and sorrow kept me at bay for years...until I finally figured out how to leave. I found one of the captains exiled to the humans' lands after the death of Captain Hirako and he helped me to disappear. I was no longer a soul reaper, nor a captain, nor immortal...but Masaki was my wife. We never thought our children would follow suit.