ADetailer helps A LOT with the face/eyes.

Although Illustrious can do a passable Guzma out of the box, this LORA makes him a bit more accurate to the anime/game's style.

Example Prompt:
Positive: guzma \(pokemon\), black_eyes, multicolored white_hair undercut, yellow-framed eyewear on head, black hooded jacket, jewelry, arm tattoo, black pants

Negative: blush, embarrassed, shota, lowres, cropped, worst quality, low quality, JPEG artifacts, bad quality, worst quality, worst detail, sketch, censored