The signs as things Izaya has done

Aries: setting his coffee table on fire
Taurus: getting stabbed on his birthday
Gemini: recommending movies to himself in a chat room
Cancer: traveling without bringing any changes of underpants
Leo: spending all day in the hospital, bored, waiting for someone to try to kill him
Virgo: knifing a guy on the first day of high school
Libra: not eating hot pot
Scorpio: getting hung up on by his only friend after being stabbed
Sagittarius: claiming to be 21 for almost a decade
Capricorn: turning his middle school biology club into a gambling ring
Acquarius: putting a decapitated head in his backpack
Pisces: punching a lamp post