Irwin is very intelligent, big, strong, and at fourteen he was already endowed with life force like that of an adult wizard strong as Harry Dresden. When in college, his power has grown so much that Dresden equates his magical force to that of Ebenezar McCoy, one of the strongest members of the Senior Council, when he gathers his will for a big spell. He is therefore capable to engage in a steady ongoing sexual relationship with a Connie, an unawakened White Court vampire, without being harmed by it. Irwin inherited his magical ability from his father. He also inherited a reserved and kindly nature from him.
In the seriesEdit
"B is for Bigfoot"Edit
"I Was a Teenage Bigfoot"Edit
In "I Was a Teenage Bigfoot", while at Saint Mark's Academy for the Gifted and Talented, Irwin is sick with mononucleosis; a black magic-powered spell operated by Dr. Fabio drains him of his life force, making him vulnerable to sickness.
"Bigfoot on Campus"Edit
In "Bigfoot on Campus", he falls in love with a newly-awakened White Court vampire, named Connie Barrowill. When Charles Barrowill attempts to wake her Hunger by having her feeding on and killing Irwin, Harry Dresden's and Strength of a River in His Shoulders's intervention thwart him.