A young woman protecting villagers in Agriss village from Yungs. Wein's party came across the village and helped her kill the Yungs. She believed that Wein was responsible for the broken dam, but Xenos explained the situation to her. She was looking for the criminals that broke the dam because of the destruction it caused, and wanted to bring them to justice. She requested to join Wein's party but he refused until she said that she knew how to get into Burnstein without passing through checkpoints.
The party reached Comsprings via the mountain road shown by Riviera and encountered Maximillian's messenger. They fought him but he fled. They went to Burnstein capital to first explain the situation. King Eliotte then ordered Wein to find the true criminal, and Riviera continued to accompany him. They found Patrick, who told them that he was hired by Wolfgang to impersonate Maximillian Schneider. Riviera wanted to continue accompanying Wein to bring Wolfgang to justice. She was revealed to be a Shadow Knight, spies for Burnstein that work behind the scenes in and intelligence operatives. Her mission from the king was to find out who broke the dam in Rolandia.
She is skilled in magic and intelligence. She is excellent in a lot of fields, but poor at cooking.
Riviera has an elder sister, Olivia, who also does the same type of work but performs tasks complementary to Riviera. Olivia acts in a support role, setting up scenarios that Riviera completes. Olivia onced loved a man named Karl who was also a Shadow Knight. Riviera was on a mission with Karl and they had to split up to evade pursuit from Rolandia soldiers. Karl promised to meet up again but he never showed up after Riviera and Olivia waited long. Riviera was depressed over this while Olivia, who was Karl's lover, was able to accept his death calmly. Riviera couldn't deal with this kind of pain again and wondered how Olivia could endure it.
From then on Riviera feared losing an important person, and vowed not to become close friends with others. She tried to keep distance from other people, but Olivia urged her to overcome the past and get back to her old self. From traveling with Wein's party, Riviera began to let her guard down and call them friends.
When Wein infiltrated the mercenary hideout by himself, Riviera waited nervously for his return. She couldn't sleep all night from worry. She was reminded of the time Karl stayed to fight pursuers to allow Riviera to escape.