Artur from the webcomic "Living with Hipster Girl and Gamer Girl" by JagoDibuja. Should work with most PonyXL-based checkpoints.
Usage tips
Strength 1.0 for keeping to the original style.
Strength around 0.75 for mixing with alternate style loras.
Prompting
3D, monochrome help a lot when put in the negatives
Base: 1boy, long hair, hair between eyes, dark hair, optionally ponytail
For the outfit: shirt/tanktop, blue pants, white footwear