[Kaioshin Sama]

Originally Posted by Akito_Kinomoto

I generally have low tolerance for the instances where the author introduces a character so powerful to the point where they can only be defeated by some illness. There are times when there is adequate set-up for this so as not to appear like a complete ass-pull, such as Fist of the North Star (you might know who I'm talking about), but most of the time it becomes a plot device when one writes themselves into a corner. Naruto is especially bad with this.

I'm going to say Souther.

Though I'd argue this cliche was actually done well in:

Spoiler for Legend of The Galactic Heroes:

Where no man is capable of killing Reinhard Von Lohengramm even though pretty much every single major character that would want to seems to give it a serious try at some point in the series. The guy easily has upwards of 20 direct and deliberate attempts on his life (maybe even more since it seems like every few episodes somebody tries to kill him) in the series and he's always able to get out of it be it from an intervention by one of his officers or just using his charisma to talk his way out of it. At one point he literally walks up to a guy pointing a gun at him and pushes his bodyguard out of the way not once, but twice as he keeps trying to step in front of Reinhard to take the bullet and eventually after talks the guy into joining his entourage. Great moment.

Anyway eventually near the end of the series he's appropriately struck down by a mysterious illness that is rationalized as him basically burning himself out at a young age and living several life times in the span of about a quarter of an average one. Basically the only person capable of killing Reinhard is Reinhard himself.