Tigerson is a supporting character encountered by the protagonist within the Unending Dungeon. He manifests as an immense black lion, far larger than average, with a thick black mane and tail. A unique tulip blooms on his forehead, reflecting his physical state; severing it causes severe weakening, and the flower visibly wilts during distress. His defining trait is absolute loyalty to promises, stemming from his backstory: 350 years prior, he and his friend Vashelle entered the dungeon. After reaching the fifth floor, Vashelle descended alone to the sixth floor to disable traps but vanished. Tigerson remained steadfast at their meeting point, waiting for centuries.

The protagonist discovers him and agrees to search the sixth floor, locating Vashelle. Upon reunion, Vashelle departs for his homeland alone, citing a ban on outsiders entering his village. This abandonment devastates Tigerson, who retreats to the fifth floor to mourn. The protagonist then offers Tigerson friendship and a home with his family. Tigerson accepts, leaving the dungeon. His ability to speak verbally astonishes the family, easing his integration into their household.

Later, Tigerson joins the protagonist’s rare items shop, attracting customers and entertaining visiting children. This role marks his ongoing development beyond the dungeon rescue, embedding him in the protagonist’s daily life and community endeavors.