Pokémon: Transcending into Diancie to Become a Trainer

Thianxi human form + system + gradually becomes a two-female-lead story + an abstract main character + certain breast-related details emphasized + Terastalization + Mega Evolution

On a dark, rainy night with no moon in the sky, our protagonist was walking along a country road, holding a beautiful-picture book of Thianxi bought from the Lich King Group.

This person was quite something, holding a pure iron umbrella in one hand while opening that little erotic book with the other, when suddenly a bolt of lightning flashed across the sky, and at the same time a phantom of a certain stinky alpaca seemed to appear above the clouds.

When she opened her eyes again, she found herself in the world of Pokemon, and had become a Thianxi. The problem was that this world already had a Thianxi.

Just then, the system binding voice sounded.

"Congratulations, host, on binding: Mythical Beast Human-Form System."

"Please strive toward becoming the world's strongest trainer!"

But the problem was that she was an undocumented outsider, and the system's identity papers only started counting from age one, so she had no choice but to stay in the secret realm for sixteen years. She even gave herself a name, Selena. Since her previous self was already dead and gone, she might as well let the past name go with it.

In the end, one day after sixteen years, Selena, under the reluctant gaze of her... sister (?) mother (?) Thianxi, set off with her little follower, Carbink, and embarked on the journey to become a Pokemon Master~~

"But... what kind of hell is Team Rainbow Rocket? Why are they targeting me, you bastard?!"

"And Yveltal, you damn bird, why the hell are you getting involved too?"