Grolem 13 (Bigum Aerum Tornadus Recyclus) is a boss character exclusive to Rayman Revolution, located at the end of the Iron Mountains. He is the fourth and last Guardian of the Four Masks of Polokus in this version. He fires icicles, tornadoes and thunderclouds. Rayman must use his magic fist to reflect Grolem 13's electrical clouds back at him, causing them to build up voltage and create a bolt of lightning, which strikes him on his weak head. The battle with Grolem 13 replaces the phase of the Iron Mountains in which Rayman pilots a warship to rescue baby Globoxes; this section becomes its own level. Unlike the previous guardians, Grolem 13 has his own unique theme music. The pillar containing his mask is also noticeably different from the previous three.
|Appears in||Rayman Revolution|
|Location||The Iron Mountains|
|Attacks||Small stormclouds, icicle throw, tornado launch, vertical lightning strike, large stormclouds, two-fisted charge, ice sphere barrage|
Grolem 13 looks very similar to Axel and Foutch. He is sky-blue in colour, and his chest is decorated with a pattern of five rings, each containing another ring. His fists are flecked with black. Compared to Axel and Foutch, whose faces are frozen in constant snarls, Grolem 13 has a 'silly' facial expression – his eyes are crossed and his tongue is sticking out of his mouth.
Rayman rides a floating blue crystal from the Iron Mountains high into the clouds. As he approaches the fourth mask of Polokus, which is trapped in ice, Grolem 13 materialises out of the air and attacks him. At the beginning of the battle, he shoots a tornado at Rayman; the entire battle is fought in midair, with Rayman using his super helicopter power to manoeuvre. One of his attacks is identical to Axel's attack – he throws icicles at Rayman. In another, more powerful attack, he throws ice boulders at Rayman which break up into smaller, yet still large boulders as they fly through the air, making it difficult for Rayman to dodge them. In another attack, which he usually performs after he has thrown the boulders, he will hold his fists in front of him and charge towards Rayman in an attempt to smash him. Another attack involves summoning a vertical lightning bolt directly down upon Rayman. Grolem 13's most common attack consists of constantly shooting small stormclouds at Rayman. However, if Rayman shoots the cloud with his magic fist, it is reflected backwards and hovers above Grolem 13's head. As more clouds gather above him, they grow darker, until the voltage grows so great that a bolt of lightning strikes out of the cloud and hits the Guardian's head, electrocuting and damaging him. This process must be performed three times in order to fully deplete Grolem 13's health. Defeated, Grolem 13 gets flatter and descends, swaying from side to side. The ice around the mask breaks off, allowing Rayman to collect it.