Onigiri (Japanese rice balls) are Okayu's favorite food, and are used as her fan mark. According to her lore, Okayu is a cat adopted and raised by her grandmother who runs an onigiri shop.[1]
Mogu Mogu, YummyFeast all reference Okayu's first original song Mogu Mogu Yummy!, which depicts Okayu as a glutton who's willing to eat anything at any situation.
Mogu Mogu (もぐもぐ) is the Japanese onomatopoeia for chewing.
Sensitive Voice skill's name is a reference to Okayu's deep, calm, husky voice which is especially appealing to listeners of all genders.[2] Its effect is a reference to Okayu's reputation as a harem protagonist among Hololive members.[3]
Before joining Hololive, Okayu actually disliked her own voice due to it being hard to hear. According to her, it is especially inaudible in karaoke in contrary to a higher pitched voice, but also when collabing, her audio sounds really quiet to the others and needs to be turned up quite a bit.[4]