Inkling Boy is the default design of the Inkling boy of the Splatoon series.
He is also the character played in Super Smash Bros Ultimate.

He will generally look like this (from Splatoon 1 and 2)
post #2913798 post #1421306

of course, he can wear different outfits, have different skin tones, and have different hair colors.
But the design in the face area (facial features and hairstyle) will usually stay the same

The moment the style of his face or hair is changed is no longer Inkling boy but should just be tagged Inkling