Rin Lion (リンライオン) is the personal RinBeast of Rio, the tragic antagonist of Juken Sentai Gekiranger (adapted in the West as Power Rangers Jungle Fury). Unlike the heroes' GekiBeasts, this mighty lion hails from the dark Beast-Fist school of Rinjūken Akugata, embodying the „shadow" side of the martial art. It made its debut alongside Rin Chameleon in the theatrical film „Nei-Nei! Hou-Hou! Hong Kong Decisive Battle." Rin Lion's huge body grants it strength on par with GekiTiger, letting it overwhelm foes with sheer force along with its fangs and a bladed tail.

Rin Lion's defining trait is its fusion ability: it locks onto GekiTouja, cloaking the robot's upper body as heavy armor while also providing a massive sword. The result is GekiRinTouja – the „true" form of the Beast-Fist giant, in which both martial-arts styles (Geki and Rin) unite for the first time. The combination is completed by Mele's Rin Chameleon, smallest of all the Beasts, which mounts onto the left arm as a whip. The team's finisher, „Geki Geki Rin Rin Zan," spins the upper body to unleash the concentrated power of all five Beasts at once.

As a toy, Rin Lion was released by Bandai Japan not as a standard standalone zord but as part of the exclusive „Juuken Gattai Special: Rin Lion & Rin Chameleon" set – a special release pairing both Rinjūken Beasts together. True to the line's DX standard, the parts snap firmly and audibly onto GekiTouja, transforming the base robot into the imposing GekiRinTouja. Because of its limited special run, the set is considered a sought-after and often hard-to-find piece among collectors.

Within Gekiranger's mecha hierarchy, Rin Lion is a key building block of the final combinations: together with SaiDain (GekiChopper's rhinoceros GekiBeast) and the remaining Beasts, the path leads from GekiRinTouja all the way to SaiDaiGekiRinTouja – the ultimate union of every Juken style. That makes the lion far more than a villain's footnote; it is the crucial link that finally brings Geki- and Rin-Juken together.