Buso Renkin
Season 1, Episode 6: The Butterfly of Black Death
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Kazuki finds Koushaku in his great-great grandfather's laboratory and attempts to destroy the Homunculus matter. However, due to the interference of Koushaku's younger brother, Koushaku is able to have the Homunculus matter attach to him and is turned into a Homunculus. He then begins to eat everyone in the vicinity until he is killed by Kazuki, who passes out from exhaustion before he is able to deliver the cure to Tokiko. Kazuki awakens to find that Tokiko has been cured and that his buso renkin shall be called Sunlight Heart.
All Episodes - Season 1
Episode 1
A New Life
Episode 2
The True Form Homunculus
Episode 3
You've Become A Little Stronger
Episode 4
Another New Life
Episode 5
To Protect Someone
Episode 6
The Butterfly of Black Death
Episode 7
Whether or not You're a Hypocrite
Episode 8
A Night in the Dorm
Episode 9
The Hayasaka Twins
Episode 10
It Seems We're Well Matched
Episode 11
Till Death Do Us Part
Episode 12
Carnival
Episode 13
Signs Of Death
Episode 14
Who Are You?
Episode 15
An Intermediate Existence
Episode 16
New Strength
Episode 17
When Dawn Comes
Episode 18
The Escape
Episode 19
As Long As I Can Protect You
Episode 20
With Strength And Spirit
Episode 21
Gone Into Flame
Episode 22
A Decision Is Required
Episode 23
Boy Meets Battle Girl
Episode 24
When You Die, I'll Die With You
Episode 25
No One Could Ever Take His Place
Episode 26
Period