Toyoko is a demon of stress.
Toyoko is a evil demon that began attacking innocents since the beginning of time. Toyoko, however, hadn't been active so much lately, due to how things continued on Earth.
However, when World War I began, Toyoko went in rage, and gave stress to everyone. Toyoko feels like everyone should live at peace, and if you don't then your unworthy. Toyoko is considered a evil fiend for wanting to make things better, he makes them worse. Toyoko attacks naturally towards innocents who are born happy, and go through hard obstacles in life, which include work, school, etc. He will steal your happiness and injected doses of stress into innocents' systems to "teach" them a lesson. Toyoko feeds mostly on hard-working people. Toyoko has been stopped many times, since going through hard obstacles in life is normal. Toyko is a demon that cannot die, but can be captured and locked away. But you have to be careful, Toyoko is very tricky, which shows why he has escaped numerous times.
The only way to get rid of Toyoko is if you give up or get an enchanted spell from a witch. Other than that, there is no way out.
Tokoyo is said to be small, green-ish, and have a pointy nose. Others have said he looks just like a normal human being. It is still unknown how his appearance is really like.