User blog comment:B214/Question and Answers 6/@comment-190.164.227.239-20161201033222/@comment-30048084-20161208151023

@BiteMetoo Issei is my favourite character as well so I don't hate him I was listing possible reasons why he can be the weakest in history.

@Swampy I agree with all your points

If you look again at what I listed as possible reasons Issei is the weakest

Physically he is not yet at Vasco's level but Vasco had a lifetime to build his body to that level.

His magical skills are still weak but as Swampy said it has only been one year since he became a devil and started fighting

Intelligence and Technique wise from volume 9 onwards Issei has grown the most in my opinion, from his battle with Sairaorg, using Samael's poison against Cao Cao, transferring the power of Ascalon into his cannons and his Fairy Wyverns overall.

Currently if Issei continues at the rate he has in only Intelligence and Technique he will surpass his predecessors that excelled in that department in no time. His magical skills might take awhile but his physical development has also been at an abnormal rate so his standing as the weakest in history won't last very long

is Issei the strongest in history? Yes he is after all his [DxD] G allows him to become a God class being.

is Issei the strongest in history without the awakening of Triana, Crimson Cardinal and [DxD]? We don't know but can assume that remains true

that's all I have to say