Train on the game assets containing Ruka-san. I prefer to set the weight to 0.6–0.9.
Sample images are generated using Counterfeit-V2.5 and Grapefruit-V4; VAE is from Counterfeit-V2.5.
Trigger it by using some of the following:
red eyes, blue jacket, blonde hair, hair over one eye, plaid skirt, <lora:ruka:0.9>