There are 2 people who will be the strongest in the end of the series. One of them is the main character Ichigo Kurosaki, and the other is the man who tied with Ichigo in their first battle Zaraki Kenpachi.

Now people will complain and say, " no the other captains are stronger" or say, "He got his ass kicked".

Him getting his ass handed to him by the emperor is no big deal why? Because even Yamamoto just got his handed to him.

Kenpachi's name means "Strongest shinigami". Basically its foreshadowing that he will become strong , VERY STRONG and end up as the strongest. He defeated 3 quincies while the other captains struggled. And on top of that he has still not unlocked his sword's powers.

So yea, Kenny-boy and Ichi-boy will be the Top shinigamis at the end of the series. And technically if you think about it (Even though there fight is considered a draw) Kenpachi was the last person standing. ;3