Son of Geronimo Toskale, armor smith in Tin Can Central. He dabbles in gunsmithing, making a wide array of cheap yet effective zipguns, and is a mechanic in training. He is also handy with a knife.
He has black curly hair and has uncharacteristically sharp, wolf-like canine teeth. Fenris internally battles with a great deal of jealousy and is quick to anger and seek revenge, but more frequently than not, he wins against the demons of his nature.
Fenris actually has some canine homologs of genes in his genome. It renders him faster and stronger than his peers, but also more sensitive to small molecules like alcohol and caffeine.
See Fenrir.
Trivia: Shigeki and Annie have dogs named Fenris and Freya.