Strength, toughness, and experience are the hallmarks of Tanbel's finest warrior. Guy is a crafty veteran, having battled countless foes and even gone up against the divine power of the Sinistrals. Taking out a little girl is cake next to that. Guy's got plenty of healing from his Tough Hide armor to see him through Shabon's damage, and his deadly weapon limits are more than enough to smash Shabon as soon as he builds up enough IP. A defensive fight is easy enough to win, especially against a child who has done nothing but feast on losers in Light.
