The Espadas are the highest class of Hollows, even the captain soul reapers have trouble fighting them. Aizen in the middle is the protagonist.
Omaiwa mo shindeiru!
He was born being able to see spirits. He started seeing soul reapers and more hollows when he's in high school. This scene is when Ichigo lost his mother.
Ichigo Kurosaki risks his life becoming a soul reaper by taking all of the powers from a soul reaper named Rukia. He did this to protect his family from a hollow.
When Aizen is attacking Ichigo's hometown village, he had no choice but to learn the "Final Getsuga Tenshou" with his father who is also a soul reaper. It's called "Final Getsuga Tenshou" because after using it, he will lose all of his powers. Aizen is kind of immortal and the strongest enemy Ichigo has ever faced. Aizen is still alive after Ichigo lost his powers. Ichigo's friend Kusuke Urahara came in and seal him away before he can even kill any more people.
Someday Ichigo met with the first ever Substitute soul reaper Kugo Ginjo. He went to Kugo's place to learn a power called "Bringer" while he is still in his human state. Later on when he finaly get Ichigo to master his "Bringer", he steals all of his power and Ichigo is now once a human again.
I'll teach you how to use the power Bringer and bring your soul reaper power back!
Rukia came back from the soul reaper society to help Ichigo get all of his soul reaper power back by putting all of her own powers into him to defeat Kugo. He became a few hundred times stronger if not a thousand. When Ichigo defeated him, he would bury his body in the human world instead of the soul reaper world because the earth is where his home is.