The Energon Pub

For whatever reason, Light Yagami/Kira from Death Note is pitted against Lelouch vi Britannia/Zero from Code Geass.

Light is allowed his Death Note, the Investigation team (Who temporarily set their sights on Zero), Ryuk (Who, as always, only gives vague hints), and Misa Amane. Lelouch is allowed his Geass, the Black Knights Zero Squadron, and C.C..

Neither knows the other's identity, and only have a basic idea of who the other really is. (I.e. Lelouch think Kira is probably on the Investigation Team, Light thinks Zero is probably a student)

Never mind the fact that one can't exist in the other's universe. Who wins?

Lelouch wins. Even if Light finds out Zero's identity that isn't Lelouch's real name. Associating Lelouch lamperouge with a long presumed dead Britanian prince Lelouch vi Britania is a fairly large leap.

Though this is coming from the first series. In the second series it would be much easier for him to home in on lelouch by working with the Britainian authorities focussed on watching him.

In true Death Note style this will end with the death of both parties.

Light will discover Zero's true identity while Lelouche uses his Geass on Matsuda to eliminate the investigation team. As soon as Light finishes writing Lelouche's name in the book in the middle of one of Zero's triumphant speeches, Matsuda comes up behind him and says "Light-kun..." and shoots him in the forehead before executing himself.

Zero collapses and dies from a heart attack while Karen cradles him crying his name in vain.

No score draw.

Ryuuk and CC then go out for apples and pizza.

And in honour of this thread:

Inferno Prime wrote:Lelouch wins. Even if Light finds out Zero's identity that isn't Lelouch's real name. Associating Lelouch lamperouge with a long presumed dead Britanian prince Lelouch vi Britania is a fairly large leap.

Though this is coming from the first series. In the second series it would be much easier for him to home in on lelouch by working with the Britainian authorities focussed on watching him.

This is why I gave Light use of Misa Amane. They wouldn't be able to immediately connect Lelouch to Zero based just on his real name, but it'd give Light a hint.

I'm not going to watch two entire series just to answer this properly. Lelouch sounds like a sleazy playboy. I imagine that he doesn't like too much light. He's going to lose to someone called Light, who always has plenty of light. Light wins.