Blaise was born to Vulcan, the Roman god of fire, and an unknown mortal mother. As with most Roman demigods and legacies, he was taken to the Wolf House when he was old enough and survived Lupa’s training. He then made his way to the Bay Area and found Camp Jupiter. He became a probatio in an unknown cohort.
Blaise is assigned aqueduct cleaning duty along with fellow probatio Claudia. While the legacy of Mercury hopes to strike up conversation with him, the son of Vulcan grabbed his pack and trash picker and ran off, much to Claudia’s dismay and disappointment.
A week later Claudia goes to the forge to have her shield fixed. Blaise greeted Claudia and he laid her shield on the worktable, studying it. When asked if he could fix it, he said, "Uh, duh. It's what I do." He began fixing the shield, but he stopped when he saw Claudia paging through a book of weapons and armor, and yelped. When Claudia realized the book was by Mamurius Veturius, Blaise explained that Mamurius is a ghost that usually hangs around the forges, but he hadn’t seen him in a week, which puzzled him, because he is always there. Claudia left and Blaise kept fixing the shield.
After Mamurius is freed, Mamurius told Blaise all about how Claudia frees him. Blaise was impressed by Claudia and swore to her that he would help her with her mission to defeat Mimi, and insisted that it be called a quest. Blaise, Janice, Mamurius and Claudia met in the forges later, and they disagreed on if they should tell Reyna Ramírez-Arellano and Frank Zhang. Blaise wanted to tell Reyna and Frank, along with Janice, but Claudia convinces them not to. Blaise then wondered if her plan would work, and Claudia pointed out it involved two of her specialties, and she was found to succeed.
The son of Vulcan then constructed a two scutum garbage can Claudia designed, which impressed her, and she wondered if she was in love with him. Blaise, Janice, and Claudia also learned how to bottle Bombilo's bakery smell. After learning Claudia was confined to her bunk, he and the others came clean to Frank and told them their plan, and outlined the plan she proposed to get the ancile back and defeat Mimi. Reyna also learned about this. After Claudia told everything to the Praetors, Reyna had praetorian guards bring Blaise, Janice, and Mamurius inside, and they told everything to Claudia and how they confessed.
Their plan goes south quickly with the wrong bag being dropped off and Frank getting hurt in a crash. The three lug their equipment to the dump as Elon guides them. They reach the dump and set up a trap outside the trailer, and after getting a nod from Claudia, Blaise threw a rock at Mimi’s trailer and ducked. Mimi falls into their trap as Claudia searches her trailer for the ancile and finds it. Soon after Frank and two eagles arrive to take them back to camp.
The next day, Janice and Blaise offered to explore New Rome with Claudia. When Blaise offered, he mumbled it and turned red as a forge fire, making Claudia wonder if he had a crush on her. Claudia denied both of them, and they went back to Camp.
Blaise is a teenage boy with long dark hair, dark skin, and a large nose. He has a muscular build.
At first glance, Blaise is very quiet and shy, and can come off as rude. However, Blaise is a very loyal friend and is willing to go along with their plans. He is very responsible though, and not as reckless as Claudia, wanting to tell Reyna and Frank about their plan. Blaise is also very thoughtful and perceptive, noticing quickly that Manutius wasn’t spending time at the forges and calling Claudia by her name after only knowing her for around thirty seconds. Blaise is also very awkward and is sometimes blunt.
Claudia and Blaise first meet when they are both assigned to aqueduct duty together. Claudia tries to talk to him, but he runs away. She later visits him in the forge to get her shield fixed. She accidentally knocks over a book and pages through it, which Blaise explains is the book of his dead half brother, Mamurius Veturius.
Claudia later goes to the forges to tell Blaise about her mission to defeat Mimi, and he swears to help her since Mamurius told him how she freed him. Claudia convinces him to not tell Reyna or Frank about their plan and they decide to meet in the forges. Claudia notes how in awe she is how fast Blaise crafted the trash can she designed. Claudia jokes in her journal about how she's in love with Blaise and how he is in love with her, but she puts a "JK" after it. Blaise, along with Mamurius and Janice, come clean to the praetors about Claudia's plan.After they complete their plan, Blaise asks Claudia if he can explore New Rome with her, and Blaise blushes and stammers, making Claudia wonder if he really is in love with her.
Blaise knows Mamirius because he is a lar at Camp Jupiter, and the two spend a lot of time together at the forges. When Mamurius stopped showing up, Blaise was concerned and didn’t know why, thinking it was weird. After Mamurius was freed by Claudia, he bragged to Blaise about how he was freed, relieving Blaise and inspiring him to team up with Claudia to defeat Mimi. Mamurius and Blaise helped defeat Mimi and also came clean to the praetors about Claudia’s plan.
Though Janice and Blaise do not know each other very well, they were not against working with each other to defeat Mimi and help Claudia. They both agreed with each other that they should tell Reyna and Frank about their plan and later came clean to Claudia to save her, bonding over their friend. They were not against working together, and both offered to walk with Claudia in New Rome.A few things they have in common are both being Probatios and both being friends with Claudia.
- Craftsmanship: As a son of Vulcan, Blaise is a skilled craftsmen, demonstrated when he built a two scutum garbage can Claudia designed.
- Forgery: Blaise has great forgery abilities and spends many hours at the forge. Blaise is an expert at repairing and building weapons, such as shields.
- Blaise is a given name derived from Saint Blaise.
- Blaise’s name could be a pun on the fact that he is a son of the god of fires and volcanoes.