|Affiliation||Guts' New Party|
Isidro is a short boy with spiky, ginger hair. His physical appearance has been noted to be similar to that of a monkey.
Isidro always dreamed to be, if not a soldier, the best mercenary warrior of his time. He is spurred to this dream by the legend of a once legendary captain, Guts the slayer of one hundred soldiers, who fought in the original Band of the Hawk. Guts never revealed to him who he was in the past, encouraging his dream nonetheless. Being a younger member of the group, Isidro really looks up to Guts as a father figure, although he insisted it is not so. He is training under Guts, hoping to achieve his dream to be the greatest swordsman in the world. Rather than teaching Isidro his moves, Guts told him to learn to fight using his own style, as each person has different strength, speed, height, and arm-reach. Isidro developed his spinning move using a cutlass, given to him by Morgan, and the Salamander Dagger, given by Flora.
While fighting against the pirates, Mule Wolcliff accused Isidro of not taking the fight serious enough: he did not use any move that seriously injures or kills the opponent. Isidro also has significant friction with Schierke, who considers him a monkey. However, the apparently cynical Isidro has shown to care, at times, for the young witch. In fact Sonia, upon hearing Schierke talking about her bond with Guts, and witnessing Isidro fighting Sharkrider for her sake, asked gleefully if the swordsman Schierke was attracted to was Isidro himself.
Even considering his character flaws, Guts shows to have some degree of faith in Isidro's qualities, encouraging him into finding a style suited to him more than Gambino did for Guts in the past. Even if refusing to label him as such, Guts has found in Isidro an apprentice, to whom has always words of wisdom and words of encouragement.
When people compliment someone or all his group Isidro and Puck normally brag about how they can manage things however both would go as far as exaggerating their aptitudes.
He may seem to fool around Schierke but he cares for her or for women as he's also shown defending Isma when she appears to be a mermaid, when Isma has no place to go he lightheartedly asks Roderick to let her stay with the Sea Horse's crew.
- In Berserk: Millennium Falcon Hen Seima Senki no Shō, he is voiced by Hiroyuki Yoshino.