Naruto: My Jutsu Train Themselves from the Start, So I Win Without Trying

After transmigrating into the Hokage world, Ye Yu had only average talent. At 20, he was still just a genin.

Even he couldn't stand watching his own ninjutsu, so he trained it himself.

The Chakra Extraction Technique trained itself and became the Senjutsu Chakra Synthesis Technique, allowing him to synthesize Senjutsu Chakra without harm.

The Clone Technique trained itself and became the Shadow Clone Technique, which then became the Multiple Shadow Clone Technique.

The Substitution Technique trained itself and became Amenotejikara.

The Transformation Technique trained itself and became the Evolution Technique. When he transformed into someone he knew, he gained all of their power.

The Body Flicker Technique trained itself and became the Flying Thunder God Technique without markers.

Ye Yu was forcefully pushed to the throne of the God of Shinobi by his own ninjutsu.