Shiggy is an orphan living at Orth's Belchero Orphanage, training to become a Delver. He holds the rank of Red Whistle, permitting exploration only in the Abyss's first layer.

He has short ashy black hair, bright-red eyes, and wears rounded glasses. His typical attire includes a plain white sailor collar shirt, khaki green or black pants, track shoes, and his red whistle.

Shiggy displays notable intelligence and wisdom, frequently acting as the orphans' strategist. He is kind and helpful, especially towards Riko, often advising her about the Abyss's dangers. His inquisitive nature centers on cartography, showing deep fascination with the Abyss's maps. He is resourceful and willing to bend orphanage rules to assist friends.

During an incident involving the Star Compass artifact, Shiggy helped Riko retrieve it after she dropped it down a hill. He intervened when the Black Whistle Cravagli found it, fabricating a story about a "clumsy woman" to shield Riko from trouble. Cravagli made cryptic remarks about the artifact being a "gazing window."

When Riko discovered Reg, an amnesiac robotic boy, Shiggy played a key role in hiding his true nature. He devised a plan for Reg to pose as a homeless orphan seeking to become a Delver, enabling him to stay at Belchero undetected. Based on his research, Shiggy deduced Reg might be an Aubade—a valuable netherworld artifact.

Learning of Riko's plan to descend into the Abyss to find her mother, Shiggy voiced skepticism about the journey's perils. Despite this, he provided crucial aid: explaining the Abyss's layers using a depth chart and arranging for Nat, familiar with the wharf slums, to guide Riko and Reg to a less monitored entry point. He bid them farewell at the Abyss's edge.

Following their descent, Shiggy remained on the surface. He was later seen listening to the Black Whistle Hablog recount stories about the Abyss's inhabitants and dangers. He also conversed with Laffi about their friend Kiyui.