Jinki is a human fighting-monster trainer and friend of Taji Sato. He is a fairly obvious parody of the titular card-battle character Yu-Gi-Oh and the main character Genki from Monster Rancher.
Jinki apparently left his world, known as Yoyomon, by way of Oberon's gate and has spent some time trying to find his way back. He appears in the context of Otter Island as a wanderer who found his way to the world of Cafe just in time to help rescue Pan the otter. He was also introduced to the world of Magimals as a wanderer, but it turned out he was much closer to his home than he ever thought. He is set to return home very soon, though it is likely he will show up again in some context later.
Jinki's most noticable feature is his hair, which stands straight out in a star shape. The tips are bright green while the rest is a vivid red. He is rather wiry, thin but athletic, and has a very large pair of eyes uncommon to Wunno. His skin, despite plenty of hours in the sun, is very fair. Jinki's favorite clothes are polo shirts with oversized collars and shorts. He always wears black fingerless gloves, a pair of goggles and a pair of yellow slip-on sneakers which transform into roller-skates.
Jinki is extremely helpful and friendly. He also makes it a point to get to know whatever world he happens to be in, and therefore usually has a great deal he can teach even the locals.
Jinki's travels are meant to be a vital clue as to the competition between Princes Mi and Selv as well as the ultimate defeat of Nexicul.