Son Biten is a sarugami youkai capable of controlling wild monkeys. She used to be an ordinary monkey living in the Yamanba Sanctuary until a certain oni, who used to be human, convinced her to devour all the spirits there. Then, one thing led to another, and she joined Yachie Kicchou's Kiketsu Family. Nemuno Sakata is a yamanba who lives within the Yamanba Sanctuary on the Youkai Mountain. She has the power to create her own sanctuaries. While she may cut a terrifying figure carrying her favorite cleaver everywhere, she is actually very kind... to anyone not trespassing on her sanctuaries.

As Biten happily and nimbly raced across the Yamanba Sanctuary, jumping from tree to tree, she heard a voice calling out to her. "Hey, Biten, I picked some nice-lookin' peaches! Wanna eat 'em together?" It was Nemuno, Biten's yamanba neighbor. "Thanks! But I'm running an errand for Lady Yachie right now, so can you wait till I get back?!" replied Biten, not breaking stride. By the time Nemuno wished her luck, Biten had already dashed out of sight. It seems they get along pretty well.

Biten and Nemuno have a few things in common. They both live in the same region of the Youkai Mountain and they wear similar clothes. It's a little strange that Biten wears the same yamanba-style clothes as Nemuno, but this probably has something to do with how Biten became a youkai after eating the spirits in the Yamanba Sanctuary.

The Yamanba Sanctuary is a region on the Youkai Mountain safeguarded from outside influences and unruly trespassers. This appears to be why ownership of this sanctuary wasn't lost following the marketplace god's incident. The retainment of ownership is evidenced by how Biten managed to transform into a youkai.

"These peaches are delicious!" After successfully completing her errand for Yachie, Biten chowed down on some peaches with Nemuno. Biten's unbridled joy was infectious, causing Nemuno to smile too. Thinking it might be nice to cook something for Biten next time, she asked what kind of food she likes. "I think I 'eard somewhere that ya like fried potatoes. That right?" Biten was about to say that was just the komainu being silly, but then she realized something much more important. "I'm gonna go share some of these peaches with Sanae!" Before she had even finished talking, she was up and racing across the mountain again. Seeing her so full of energy, Nemuno laughed as she waved goodbye.