The Legend of Korra knew how to raise the stakes higher than ever before. Two of the show's biggest season finales ended in titanic clashes with giant villains straight out of a kaiju film. In Season 2, Korra's uncle the conniving Waterbender Unalaq, fused with the spirit of darkness Vaatu to become the city-threatening UnaVaatu. The next giant-sized villain came with was in the series' finale when the Metalbender Kuvira piloted a massive mecha war machine. Though fans never had the chance to see the two colossal figures face-off, we have to wonder: just who would win the battle of giants if they ever did?
Despite their many differences, both combatants have many similarities. Both were multi-story tall antagonists besieging Republic City with devastating force that resisted the United Republic's military and forever changed the landscape of the city itself. Both were too powerful for any one bender to stop, and both provided monumental struggles that tested the heights Avatar Korra's abilities could ascend to. In comparing the power level of the two it is important to consider what exactly each combatant was capable of.
UnaVaatu retained Unalaq's prowess with waterbending on a massively increased scale. UnaVaatu not only lifted a gargantuan tidal wave that swept through the United Republic's naval armada but even used spiritbending to nearly destroy the very essence of Korra's being. He was able to unleash spirit vines throughout Republic City, and the vines themselves were so powerful that even years later, they remained a distinguishing feature of the city.
UnaVaatu seemed nearly impossible to stop. He took the entirety of the United Republic's offensive attacks without any visible effect to his wellbeing, and it was not until Korra arrived in her own giant energy form that any meaningful force opposed him. UnaVaatu's energy beams tore through Republic City and brought down blimps from the sky. However, these are all traits matched or exceeded by Kuvira's mech.
Kuvira's mech proved almost unstoppable in its own right as it tore through the city. Its energy canon was its primary weapon, devastating entire buildings, city blocks and at one point sweeping across the skyline to destroy a huge swathe of the city itself. Its platinum hide was not only invulnerable to metalbending, but showed no damage from attempts at melting it with lava or even toppling entire buildings onto it. Its physical strength pushed through buildings and busted out of ice.
The mech had more specialized abilities that proved challenging for those trying to find a way around it. It was unaffected by EMPs, could reach around every angle of its body to fend off attackers and even had window-washing units designed into its viewing plates in order to clean off any attempts to obscure its pilot's vision. While such tricks are useful, however, a bout with UnaVaatu would come down to a clash of sheer strength and raw destructive power.
It's clear a battle between these two giants would completely level any surrounding city. In the end, however, Kuvira's mech would come out on top. While the spirit of Vaatu may be one of the mightiest beings in existence, the mech's energy cannon harvests the same energy he uses to an even more brutal effect. When Korra redirected its blast at point-blank range, it ripped a hole in space-time itself, opening a new spirit portal. As much firepower as UnaVaatu resisted, he never withstood an attack on that scale.
For comparison, Kuvira's mech shrugged off the combined assault of Avatar State attacks along with dozens of Airbenders and some of the world's best Earthbenders. It was only by miraculously piercing its hide and bringing it down from the inside that Team Avatar ever defeated it, and UnaVaatu just would not be capable of doing the same. Such a titanic showdown would be a sight to behold, but in the end, it's the Great Uniter who would come out on top.
