Hold up. I don’t think we should think which of those two won, iI think it’s who won. Many people might not like my theory, but I think both of them won and lost in a way. Let me explain why.. L wanted nothing more than to catch and kill Kira/Light. It was his biggest wish. Now L won and lost. He completed the first part of finding Kira, because he knew that Light was Kira, just couldn’t prove it to others. The second part however, not so much. He died before he got to kill him, and Near had to finish off. (I mean ryuk in the end but well). So he got his wish, when Light died, but didn’t do it, because L died before he was able to. Therefore I think he won, but lost to Kira. Now Light or Kira in the other hand. He wanted to become a god of the new world, and kill anyone who tried to stop him. (Originally criminals but later on innocents), but died trying to achieve it. He kind of stayed as a some sort of a god even after he died, since he still had worshippers on earth. And (i believe the shinigami theory, cause it seems really possible and well proven) when Light became a shinigami, he became a GOD of death, he wanted to become a god of the new world, and he became a god of death, but died in the human world. For that i’d say he also won but lost. If he would remember his human life when being a shinigami, then he would have won, because he could just continue his killing as a ahinigami, that’s not the case tho. Therefore i think L and Kira both won and lost to each other, both got what they wanted but suffered and died at the same time.

Hold up. I don’t think we should think which of those two won, I think it’s who won. Many people might not like my theory, but I think both of them won and lost in a way. Let me explain why. L wanted nothing more than to catch and kill Kira/Light. It was his biggest wish. Now L won and lost. He completed the first part of finding Kira, because he knew that Light was Kira, just couldn’t prove it to others. The second part however, not so much. He died before he got to kill him, and Near had to finish off (I mean Ryuk in the end but well). So he got his wish, when Light died, but didn’t do it, because L died before he was able to. Therefore I think he won, but lost to Kira. 

Now Light or Kira in the other hand. He wanted to become a god of the new world, and kill anyone who tried to stop him (originally criminals but later on innocents), but died trying to achieve it. He kind of stayed as some sort of a god even after he died, since he still had worshippers on Earth. And when Light became a shinigami (I believe the shinigami theory, cause it seems really possible and well proven), he became a GOD of death, he wanted to become a god of the new world, and he became a god of death, but died in the human world. For that I’d say he also won but lost. If he would remember his human life when being a shinigami, then he would have won, because he could just continue his killing as a shinigami, that’s not the case though. Therefore, I think L and Kira both won and lost to each other, both got what they wanted but suffered and died at the same time.