Why is the Shadow Shaman called Little Y?

"Little Y" or "Little Crooked" are names that come from SH's appearance.

SH's body will be tilted a bit when he adds medical waves, and in the Sea of Clarity, SH's 30 is also dancing in the air, but it is also lifting a leg, tilted look.

So, it's a habit to call out and call out, and it's a habit to call out.