Tokoro Tennosuke is a walking, talking, blocky, human shaped mass of tokoroten (a type of very cold jelly). His moldable body makes him compareable to Gumby. His Japanese name is a pun on "tokoroten", hence his ability to shape himself into any form. His name in the English dub is probably a trademark-friendly reference to Jell-O Jigglers, a snack made from fruit juice and powdered gelatin.
Tennosuke appears, at first glance, as the most serious of the main Hajike trio of the series. Not as necessarily happy-go-lucky as either Bo-bobo or Don Patch, Jelly tries to remain calm while merely performing his strange actions. However, his serious nature hides the extremely emotional and over-the-top emotions that the wobbly warrior exhibits. His moments of calm are contrasted to periods where he could be angry, upset, even silly like his comrades. The contrast between his serious and his emotional sides are reflections of his period at the supermarket, being forced to try and get himself sold and the usually emotional followup from the disappointment of remaining unused for his primary objective of consumption.
By the time he officially joins Bo-BoBo's team, he possesses a handkerchief with the Japanese hiragana for "nu" (ぬ) written all over it (ぬのハンカチ, the "handkerchief of 'nu'", known in English dub "The Lucky Hanky") which he uses to wipe away tears at first, but eventually leads to an all-out "nu" obsession. By contrast he utterly despises the hiragana character, "ne" (ね)! Besides the ne character, Tennosuke will not tolerate tofu. The tokoroten man despises it with a passion, to the point where his worst nightmare is being tortured by tofu men! This hatred could stem from the fact that tofu sold even better than he did while in the supermarket, or it could be a simple rivalry with another squishy food.