BLEACH (Burichi), by Tite Kubo. First published in 2001, and first published in North America in 2004.
PLOT:
Ichigo has always been able to see ghosts, but he doesn't consider it a big deal. It's just one more complication in a busy life full of school, siblings, and his family's medical clinic. That ability becomes a big deal when a Soul Reaper named Rukia shows up in his house to fight an evil spirit called a Hollow. When Rukia is injured, she insists that Ichigo take part of her power to continue the fight. Ichigo accidentally takes it all, forcing him to take on Rukia's role of keeping the balance between the human and spirit world while Rukia figures out how to fix things.