Rie Harui’s name may not ring a bell among fashion watchers, but her fledgling jewelry brand, Riefe, certainly does.

A longtime protégée of Yohji Yamamoto, Ms. Harui, 42, is one of the few jewelry designers in the fashion world to co-sign pieces produced for a leading designer in addition to running her own independent brand. Not even Loulou de la Falaise, Yves Saint Laurent’s longtime muse and accessories designer, received such a spotlight.

By turns brutalist, punk and slightly surreal, Ms. Harui’s eye-catching creations for Yohji Yamamoto by Riefe often draw on tooth and claw: For the fall 2024 men’s collection, presented in Paris in January, a visit to Kruger National Park in South Africa gave her the idea of imitating deer antlers in a bony-looking necklace of brass and silvered bronze. Crocodiles observed in the wild became the springboard for a knuckle-duster ring in textured, blackened sterling silver, fingerless chain mail gloves and an open-front chain choker in silver alloy and leather, punctuated at each end with a spiky denticle.

In an interview after that men’s wear show, Mr. Yamamoto said that he had never once given Ms. Harui a design brief.

“We work almost every day together, and we’re exchanging our sense of beauty,” he said. “Mentally, we became so close. I don’t give her my mentality. She just gets it by feeling. She’s not afraid of anything. She is so brave. Maybe she’s a genius.”