Momoiro (鈴優桃色, Suzuyuko Momoiro), also known as the Pink Mechanic, is a young girl who enjoys her job as a B-DaMechanic deeply, fascinating herself with the potential of machines and dedicating as much time as possible into creating the best B-Daman for her closest friends. She is Ren's best friend.
Momoiro is overall a pleasant company for many people, with the emotional capacity to sympathise with anyone and everyone. She's not the most social person around, but she cannot find it in her to ignore someone in need of assistance; she considers this a flaw of hers, especially due to its time constraints.
She, however, can also be strict and motherly-like to her closest friends, notably to Satoru because of his playful personality. This attitude is mostly out of pure concern, and she notably never steps into the zone of actually scolding anyone.
Momoiro also has an occasional playful side to her, having the hobby of teasing Ren whenever an opportunity shows itself.
Momoiro has always looked up to her father, who was a great B-DaMechanic to her very own eyes. His work has always inspired her as a young child. Although she was constantly requested to be a B-DaPlayer by him, she ended up taking the path of a B-DaMechanic.
When she moved to Liken as a small child, she meets Ren and opens her up to the world of B-Daman. Since then, the two has been close friends throughout and Momoiro always likes to share stories with Ren.
In the beginning of the season, Momoiro remains in Liken to study B-Daman parts further, learning about legendary B-Daman and in attempt to understand why they were legendary she begins a long and thorough research in the difference between each B-Daman.
Her research was halted when she learns of the Winner's Tournament in town, leading her to contact Ren and meet up with her at the venue, promising Ren that she would support her with all her might.
Remaining as a spectator at the tournament, Momoiro would occasionally drop by the training room and do maintenance on Ren's Masked Delta, making sure it's always in tip top shape.
On one of these visits, she ends up meeting Satoru who was weeping over his loss in the first round. Momoiro learns that the boy was completely new to B-Daman and only participated for the benefits, and asks if he would like to get better at it. When Satoru agrees, Momoiro immediately gets to work to have a B-Daman ready for him the next day, introducing Ren to him then with a request that Ren teaches Satoru the basics of B-Daman, out of the thought that the two would greatly benefit from having B-DaPlayer friends.
After the Winner's Tournament, they return to Liken with Satoru in tow. Momoiro continued to support Ren and Satoru in their practices, handling their daily meals and improving their B-Daman. When questioned by Ren, Momoiro admits that she enjoys spending her time like this; a peaceful environment where she could support her friends to the fullest. She begins talking about her father as well, and the types of invention he had created for his many customers. His great contribution to the development of B-Daman inspired her greatly, and relating the story once more gave her the motivation to continue working.
She then opens a temporarily assistance shop for free B-Daman maintenance in town, attracting many kids over to have their own B-Daman created. Ren and Satoru occasionally assist her in teaching the children, but there were experienced ones to cover the role otherwise. This lasts until the Neo Shadow Alliance invasion, to which her shop gets defended by everyone long enough for her to pack up her necessities. Immediately after they retreat, following Satoru to his home in Neon City.
Requiring to be defended long enough back at Liken made her extremely guilty, and she doesn't waste a time to apologise to everyone upon their arrival. She's only been playing the support all this while, and she felt that it wasn't enough against such a major world crisis. Ren comforts her right away, stating that it's because of her support that all of them were able to escape from the grasp of the Neo Shadow Alliance. In surprise Momoiro begins to tear up, agreeing then that unlike her father's wants, she was more suited to be a B-DaMechanic, supporting her closest B-DaPlayers with everything she can. She joins the rescue team in the city after.
Momoiro continues her work in Liken, using the basics of B-Daman she learnt during her experience in helping Neon City to further her machines' capabilities. She also came in contact with Liena and Mie, occasionally exchanging video calls with the duo. When she hears Liena wanting to become a better B-DaPlayer, she offers her the opportunity to fix up her B-Daman.
Ren soon returns to town upon news of the strike shots, requesting of Momoiro's assistance at deciphering B-DaMage's hints. Momoiro willfully helps with this, and with enough time and luck she discovers one of the hints to be closeby Liken. The strike shot Ren obtains proved to be challenging for her to use, however, and in her worry Momoiro asks if she could observe her, providing her with a chance to see if it was the machine that wasn't able to handle the strike shot's power. But no matter how hard Momoiro worked and improved Ren's B-Daman, the latter was still unable to master the power of the Masquerade Shot. Ren regardless thanks her, admitting to noticing great improvements in her shots after so much work.
The duo remains in Liken until the time of the tournament, with Ren passing on her chance to participate for more time to understand her strike shot's potential. In turn, Ren this time offers Momoiro her support and meals as Momoiro continues her job, adapting her creations to handle strike shots both as the user and a foe.
As the tournament nears, Momoiro repeatedly contacts Satoru, only for it to come to failure. This was later explained by Satoru when they meet at the stadium, and unlike Ren Momoiro couldn't find it in herself to not forgive him. She joins Armada in the audience alongside Ren.
After the tournament, she heads back to Liken to begin deeper studies on the parts. She discovers the cartridge system in a call with Liena as soon as they were created. Deciding to test the new concept, she requests the blueprints from Armada and creates demo cartridge systems for both Ren and Satoru. As the announcement for the match between Yamato's Team and B-Deus was announced, she heads for the stadium as a spectator to cheer Yamato's team on.
After the season, she, along with Ren and Satoru, agrees to hang out with Yamato's team.
Momoiro joins Armada's group following the situation with B-Deus because she came to the realisation that by joining the Master she would be able to follow up with the newest systems as soon as possible. She becomes close friends with Bull.