Not true at all. AI image generation is very good now, especially for anime. SDXL models would work perfectly I think. So many tools are available; poses for example, can literally be fully customized through a pose editor.
The only hurdle would be getting good images for the data set to train a character LoRA. You'd have to rip his art from the game and hope they are in good quality/resolution. OR use AI to create the data set, which might actually work better in this case.
And I am talking about running an actual local AI img generator on a personal machine If that wasn't clear. Not those trashy websites that offer free/paid services.