A runaway brat turned thief, Isidro dreams of becoming a great swordsman, which led him to follow Guts. Despite his lack of strength and skill, he uses his small size and agility to his advantage, along with various tricks and tools. His ego is enormous, and he initially aimed to "observe" Guts and steal his "techniques" to surpass him. However, he gradually realizes the vast difference in strength between him and Guts but begins to see potential paths for himself to become a formidable warrior.
His most important role, however, is likely to provide comic relief alongside Puck.
