Gaspar Martínez (unknown – 1491) was a prosecutor for the Spanish Inquisition's tribunal in Barcelona during the Renaissance. He was responsible for ordering the arrests of Assassins in that city, though he was under the impression that they were little more than atheistic heretics. For this, he met his end at the hands of Italian Assassin Ezio Auditore da Firenze when he arrived in Barcelona to save the Spanish Assassins.
In 1491, Gaspar Martínez was charged with the task of arresting Assassins who operated in Barcelona. Gaspar, like his other colleagues, was ignorant of their identities as Assassins, or even of the order's continued existence, but nevertheless pronounced them heretics in light of their atheism. Their names, in fact, had been supplied by the Grand Master of the Templars, Rodrigo Borgia, who took full advantage of the Inquisition's religious persecution to destroy his enemies in Spain.
On the day that one of these Assassins was to be burned at the stake, Gaspar chose not to be present at the execution. Instead, he was taking a respite on a balcony when he was confronted by Ezio Auditore da Firenze. Alone, he was easy prey for the Italian Assassin, who unbeknownst to him had come from Venice to rescue his fellow Assassins and had been directed to him by Raphael Sanchez.
Gaspar suspected no danger as Ezio questioned him about the arrest of the Assassins. To this, the prosecutor only retorted in disbelief that Assassins were nothing but "medieval phantoms", but Ezio countered that the arrests had been too systematic for him not to have known of their affiliation. Still dismissive, Gaspar brushed the topic aside, arguing that the imminent public execution rendered it a moot point anyways.
With Gaspar's back turned, Ezio gave him parting words of contempt before killing him with his Hidden Blade. After retrieving a list of Zaragozan Assassins from Gaspar's corpse, Ezio would then race across the city to the site of the execution, rescuing the young Assassin from a fiery demise.