Нет. Слова автора на реддите - "I did not generate these with AI. I use Procreate on the iPad to draw, and Photoshop to add effects and adjust colors. I spend a lot of time referencing stills from anime and sketching out a layout / concept before starting a piece. Each piece takes around 8+ hours from idea to completion."

Возможно для прототипирования использовалась нейронка.

Нет, не нейронка