Of the Thirteen, Onyx Prime, the "Lord of Beasts", is the most spiritually-minded of their number, in tune with both the creatures of the natural world and the intangible realm of the spirit. He alone has the ability to properly use the three-faced Triptych Mask given to him by Primus; this artifact allows him to cast his spirit across vast distances to commune with the dreams of far-off beings, or even track the journey of a Spark across the afterlife. Though some view these strange mental voyages across distant realms as mere flights of fancy, Onyx and his visions make him one of the most inspirational Primes.
Onyx Prime's spiritual aptitude allowed him to cultivate an inscrutable presence that made him appear mysterious and slightly intimidating at the best of times, even to the other members of the Thirteen. In spite of his powers, Onyx Prime is a kind-hearted and friendly individual at Spark, a trait that made him one of the most liked members of the Thirteen. Indeed, all of his siblings treated him as a fiercely loyal companion and a steadfast confidant—Micronus Prime, in particular, once regarded Onyx as his closest friend. As the first Transformer to possess a beast mode, those Transformers who revere him as the greatest of the Primes tend to eschew the vehicular alternate modes of other Transformers, preferring to wear the animalistic forms exemplified by their spiritual progenitor.