The Metalero is a prominent warrior and blacksmith that forges weapons built to fight supernatural beings.
As Carlos Trese went on to be a Mandirigma, he was mentored by the Metalero. He forged blessed iron into twin swords for Carlos to use, each forged with the soul of a forgotten hero. Out of caution, he named the swords Parusa and Sentensiya.
When the Trese family's fifth child was stillborn, her soul was brought by the fastest tikbalang to the Metalero. With the assistance of the Babaylan of Makiling, he forged her into a kris, named the Sinag, that was eventually given to her twin sister Alexandra Trese on her 18th birthday.
A dismembered Bantay appeared in his workshop, having barely escaped with his life using a Dragon's Gate inscribed in his bandana. Carlos paid him a visit as the Metalero forged a metal attachment to act as Bantay's prosthetic, both functioning as an arm as well as a wepaon.
Alexandra brought Oriol the Enchantress' demon claw to the Metalero to be forged into bullets. After three days, the bullets were finished and loaded into the Kambal's Armas Infinitum to kill Dr. Karl Burgos and stop the raging fire in Cubao.
One day, Carlos visited him while he was forging metal, relaying the threat of four gangs of taga-dagat invading the mainland. Hungry for adventure, the Metalero decides to join his cause. Together, they visited Bantay and waited for him to finish his underground fighting match against a bungisngis in Marikina. Metalero pointed out how he wasn't using the metal prosthetic he made him during the match, but Bantay said that he only wanted to make the fight fair. After some convincing from Carlos, Bantay decided to join them. After Bantay helped them gather Dolph and Ting, Alexandra called Carlos and informed them of the taga-dagat already starting to invade Barangay Pacifica. Carlos and the rest of his squad immediately responded and went to the barangay under siege, with the addition of Hank Sparrow to drive them through the floods on Dolph and Ting's boat.
Metalero helped Carlos and Bantay fend of the taga-dagat approaching their boat, defending themselves and the survivors Seepul was boarding onto it. However, the boat was capsized by several taga-dagat pushing from below, making everyone inside fall into the flood. Dolph and Ting assisted them in fending off the creatures in the water and Hank found a roof to serve as a small platform for their Metalero and the others to stand on. This was also collapsed by the taga-dagat, with one pulling Metalero from below the depths of the flood. The taga-dagat grappled with the Metalero underwater, severely injuring him, but was ultimately stabbed through the head by the Metalero's sword. Falling unconsious, the Metalero lost his grip on his sword as another taga-dagat tried to grab the opportunity but Ting killed them before they could. Dolph then brought him to the surface, where he hung on some driftwood to stay afloat.
Rakuda, seeking to expediate their offering to Bagyon Yente, ordered the taga-dagat to take a dosage of Shift Pills, transmogrificating them into stronger creatures. At this point, Alexandra Trese arrived with the Kambal and Amang Paso, who used Boyet as an entrance to the duwende tunnels for the survivors to go through. Seeing that both the Metalero and Carlos are floating vulnerably, Rakuda goes after them. He threw Metalero in a hasty attempt to get to Carlos and drown him, seeking vengeance for all the comrades he killed. The Metalero landed near Alexandra, calling her attention to danger her brother is in. Thinking fast, she threw the Sinag at Carlos, who called it to his grip and gravely injuring Rakuda in the process.
Metalero stayed behind for most of the fight, weakened by his injuries. Eventually, Carlos managed to lead an assault on a superpowered Rakuda, having used another dosage of Shift Pills with the other taga-dagat to transform him into a gigantic creature, and killed him with the help of a Dragon's Gate. Bagyon Lektro arrived and revealed that she intended to take the 400 dead taga-dagat as an offering instead, with permission from Datu Karagatan and the Madame. After the battle, Alexandra healed Metalero and the others' injuries and helped them recover.
After the battle, Metalero was invited by Hank to have a meal with everyone at The Diabolical. During the meal, Alexandra warned them of the impending danger of the Madame and how the city would need their help once again, to which Carlos gave them a hearty toast being honored to fight by their side once again.
- Sinag, Alexandra's kris
- The Armas Infinitum. the Kambal's eldritch pistols.
- Hank's "Ama, Anak, at Espiritu Santo" shotgun.
- Bullets made from Oriol the Enchantress's claw.
- Carlos Trese's twin blades, Sentensiya and Parusa.
- A wing glider for Alexandra to reach the Manananggal Queen's lair.
- The Kambal's Super Lolo Trese Stars, which are thrown explosives.
- Bantay's metal attachment, which both functions as his left arm as well as a multiple use weapon.
- The Metalero is a reference to Carlo J. Caparas' classic comic book character Panday.
- The Metalero has an unnamed brother that has not been directly shown in canon as of now. This person has access to the Metalero's earliest creations.
- According to the initial skteches of Jimmy Trese shown in Trese: Shadow Witness, Kajo Baldisimo envisioned some of Jimmy's equipment as being fashioned by the Metalero. Kajo's comments however do not specify which equipment and Metalero's involvement in Jimmy's equipment has yet to be established in any of the stories.