Ricardo's relationship with Anastasia, and his membership in the Fang of Iron, spanned for more than 10 years. After Anastasia pledged to remove Ricardo's collar, he pledged his alliance to her. He had confidence in Anastasia's dreams for the future and her talent and thus decided to stand beside her to watch her legend grow.
Ricardo was suspicious at Garfiel's relationship with Mimi at first, but when Garfiel transported the near-dying Mimi to the hospital, Ricardo shows him his gratitude by giving him a Saikeirei-like bow and treats him as a companion.
Despite being a lower class and being Anastasia's knight, he views Julius as a trustworthy ally and a comrade. When Julius began to doubt himself during the events of Arc 5, Ricardo lifted his spirit and removed any doubt he had. He sacrificed his arm to save Julius from being killed by Roy, but Julius's name was eaten and defeated regardless. Even though Ricardo doesn't remember Julius, he still lifted his spirits.
Sometime in the past, they were abandoned by their parents and adopted by Ricardo and Anastasia ever since. In the events of Arc 5, Ricardo recklessly attempts to find Mimi alone, even if it means disobeying Anastasia's orders.
Ricardo showed respect towards Subaru during the events of Arc 3. When Subaru noticed Ricardo was wearing the Hoshin logo, he figured that he knew Anastasia. Ricardo introduced himself in both name and race (as a kobold). On their way to the Flugel Tree to fight the White Whale, he complimented Subaru's ground dragon Patrasche and lifted Subaru's doubts about the outcome of the fight. Subaru realized that Ricardo and the members of the Fang of Iron were riding large wolves called Ligers. He asked him a question about whether a large beast man riding a large wolf made it a bit awkward. Ricardo didn't mind it, however, he warned him not to ask that question to the others as he considered that question offensive. During the fight against the White Whale, he saved Subaru by taking the hit, sustaining major injuries in the process. In exchange, he gave Subaru a message that the whale was "lighter". This gave Subaru a fighting chance.
During the events of Arc 3, Ricardo met with a tied up captive named Otto. While Otto bawled his eyes out, Ricardo handed him a tissue and tried to tell him jokes to cheer him up, but at the same time, he told Otto to man up. This gave Otto hope and the motivation to live. He also promised that he'd keep their conversation a secret.
Five years ago before the plot of Kararagi Girl & Cat's Eye, Ricardo was beaten and thrown into a prison of sorts for slaves. He was repeatedly beaten and tortured until he met Reisel. Reisel offered his help in exchange for Ricardo's strength whilst they worked as slave labourers in the mines, and that allowed Ricardo to escape from the beatings. One day, Reisel organised a slave rebellion and both he, and other slaves escaped, however he did not invite Ricardo to it. As a result, the guards took their anger out on Ricardo and beat him nearly to death, as a result of that Ricardo looks on that situation unfavourably. However, Reisel apologised years later, and Ricardo still felt like he owed him a debt for the time Reisel saved him from the torment of his gaolers. After then being betrayed by Reisel, Ricardo destroyed Reisel's shadow clones using his Resonance Wave having directed his anger and frustration at him.
In the events of Arc 5, Ricardo felt a bit creepy and a chill down his spine when Roy happens to know his name and history with Julius and Anastasia. Roy is the one who cut off Ricardo's arm.
In the story Kararagi Girl & Cat's Eye, Shiroro nearly beheads Ricardo as they fought after a failed ambush attempt on a good shipment that Shiroro was guarding. They eventually came to a truce and remained on cordial terms with each other after the fight.