Being a pixel art LoRA, you need to generate at 1024x1024 exactly.

Then downsize by 8 to 124x124 using the pixel art extension of your choice, or nearest neighbor scaling in your preferred program. Some manual cleanup will be necessary if you want to look perfect.

LoRA strength: 1.0-1.7 (May not cooperate with all Illustrious-based checkpoints. Gallery examples use Nova Anime XL)

No trigger word, but I do recommend the following tags: solo, simple background, blue background, thick outline, looking ahead, cowboy shot,

Optionally, you should probably do "leaning back" or "leaning forward" to match Battle's heavily exaggerated poses.

Negative prompt tags: blurry, white outline, looking at viewer

Adding "blurry" to your negative prompt seems to also maybe help.

EDIT: Using Arzeth's Sonic Battle Style LoRA (linked below) at around 0.6 strength along with this helps a lot with the outlines, shape, and proportional consistency of the game's art style. See my most recently gallery post below for examples.