A battle of wits, minus the plot
Death Note is mostly two very smart people trying to outthink each other, with everyone around them reacting to the pressure. This quiz keeps the part about how people think and leaves the story out. It matches you with one of seven characters based on how you handle rivals, secrets, riddles, and the people who underestimate you. The questions never mention the series, and the result pages describe personality rather than plot, so there are no major spoilers if you're still partway through.
The seven in the lineup
Light Yagami is the top student with a polished smile and a very firm idea of how the world ought to work. L is the strange, brilliant investigator who sits however he likes and trusts nothing until he's checked it twice. Misa Amane is a bubbly model who commits to the people she loves completely and all at once. Near is calm and patient, cool enough that people mistake it for distance. Mello is restless and competitive and would rather gamble than wait. Ryuk is the bored onlooker from somewhere else entirely, who mostly wants something entertaining to happen. Touta Matsuda is the eager rookie everyone talks over, right up until he surprises them.
Your result page goes through what your character does well, where it trips you up, and which of the other six you'd get along with best.
No detective work required
You'll get twelve small situations: a rival who just beat you, a riddle nobody can crack, a stranger offering you an unfair head start, a 3 a.m. you're somehow still awake for. It takes about two minutes, it's free, and there's nothing to sign up for.
Where the series came from
Death Note was written by Tsugumi Ohba and drawn by Takeshi Obata, and it ran in Weekly Shōnen Jump from 2003 to 2006. Madhouse's anime adaptation followed in 2006 with 37 episodes, and it's still the version most people start with. Part of why the characters stick is that almost nobody in the story is simply good or simply bad. They're clever, stubborn, devoted, or bored in ways that get them into trouble, which makes them surprisingly easy to see yourself in.