strongest anime character

I'm sure Kyubey could stand up to the powers of anyone, if the correct wish is asked. Unfortunately with that clause, he is limited in scope. Ultimately Madoka did win, but only because of her friend going through all that hassle.. So I would think it would have to be Madoka plus Homura equals Kyubey defeat. (Until someone makes a wish that counter's Madoka's.. Which would be very interesting..)

You are looking at it the wrong way. The Power to grant certain levels of wishes isn't Kyubey's. Kyubey can't grant any wish, and a person can not just wish away Madoka's wish. The reason her wish was so powerful is because Homura went through many universes in time building up Madoka's power to be Godlike. The Madoka that is in the series is Madoka (granted she wouldn't be so powerful without Homura, but her existence is still valid and powerful). Madoka's godlike wish was granted only because of how powerful she was. If she was weaker the wish would not have had an effect like that. Also Kyubey was never "defeated". He was an impartial being that focused on logic. Kyubey's mission was to balance out the universe's energy, and he accomplished his goal (madoka just changed the game by changing the way energy works, but Kyubey still didn't lose anything).

(Well.. originally I was trying to stay as spoiler free as possible...) After doing some reading I will concede that Kyubey isn't the most powerful anime character, although I only meant he was one of many. I still don't know what to say about Madoka however. Ultimately she was powerful, but her abilities only stretched to a very narrow point. She could do one thing, but throughout all time, space, and dimensions. Making her powerful, but not a real god. However, her actions did change the course of reality, so I would say it is up in the air for me. I know he wasn't technically defeated. Since he is more akin to a misguided hero type than an outright villain. Still, he was forced into going another path because reality shifted. He didn't succeed in his goal, because in the new reality he travels with the magical girls to stop the grief demons. Which to him is a far more inefficient manner (in essence, he lost the "easy" way of doing things, though he isn't aware of it.) So technically his quest is still on going, (Though I do hear there are some spin-off mangas that might explain more.)

tenchi because he can move at the speed of light and throw galaxies like they are shurikens. Not to mention he is the avatar of a god.

That is a very hard question to ask because there is so much anime out there. Though im sorry im gonna have to go with the anime i have watched so far and say Goku no offense to you Xanxus.

Okay that's a tough because some are great at killing for a trade without being killed. Others are physically strong. Why don't we get specific. Who do you think is best killer. Strongest and mentally strong. I give up they all have weaknesses this is a job for ultimate warrior. Lol

If Layfon took Goku down, wouldn't his Saiyan blood just make him stronger? >.> But, I'd have to say Atomsk is pretty bad ass.

are we talking about physical power here? if we branch out of that then I guess I'll have to say Simon and the Gurren-Den, the spiral power of humanity that never ends