Since University the keywords fusion and hybridity were at the core of his methodology, and after bringing them to the Netherlands, he named it the Monster Project. Onuma finds inspiration via daily life experiences (anime, hip hop, fashion) and symbols of capitalism (iphone, sneakers) and incorporates them into his own creations. By extracting symbols from the tangible world he transfers them onto his intangible world.

According to Onuma, the monsters act as a speculative place that not only allow him to output the combination of his diverse interests and experiences into Japanese and Western styles but also as devices that hold his memories and origin of Japan. He wants to transcend the dualism of figurative and abstract, and interprets the concept of monsters as a convenient tool that can include both figurative and abstract. ‰ÛÏA monster is a bridge between figurative and abstract‰۝.