Nobuharu is a 32 year old from a present-day Japan who works odd jobs.
Koda is a 100,000 year old caveman who did not age due to being bonded with an Energem.
Nobuharu is first known to Daigo and Amy, due to not trusting his identity until Amy does
Koda is first known to Chase, as the two were the first to become Rangers
Nobuharu likes to make outdated puns and jokes; referred to as "old man jokes" by his teammates. Yet, even unable to control himself from doing so when in a crisis.
Koda having been out of commission for millennia, he cannot speak English properly yet and has a hard time learning to adapt to modern society.
Nobuharu is nicknamed Nossan, based on his first name and age (ossan [おっさん] means old man).