Warning: Contains spoilers for the One Piece manga.
Summary
Gear Five's white color may represent sunlight, connecting to the energies of the Ancient Kingdom. Luffy's unique coloring on the volume cover hints at a deeper connection between Nika and the Ancient Kingdom. Vegapunk's dream of abundant energy is tied to solar energy, which is likely linked to Nika's energy source.
A piece there's a genius reason to explain one of Gear Five's biggest mysteries, and it may have been confronting fans from the start. One of Gear Five's strangest, inexplicable features is that it mysteriously turns Luffy's hair and clothes white. When Gear Five first appeared in the manga, many people assumed that its official color would be yellow rather than white due to its connection to the Sun God Nika. The reason for Gear Five's color scheme has never been truly revealed but the cover of A piece's latest episode may provide some answers.
Volume 108 of One Piece features several key characters from the Egghead Arc on the cover, including Gear Five's Luffy, who is featured prominently in the middle. The volume's cover has attracted much attention, especially due to Luffy's unique color, which differentiates it from the other characters in the illustration. In fact, Luffy's multicolored shadows are very similar to refracted light, almost as if Luffy's Gear Five is made up of light itself.
This raises the possibility that Gear Five, or rather Nika's true form, may not represent the sun but sunlight, which is actually not yellow light but white light, thus explains Gear Five's white color. Additionally, Nika representing sunlight could fit into Vegapunk's hints about the mysterious source of the Ancient Kingdom's power, as well as one of Luffy's most curious powers.
One Piece hinted at the real reason behind Gear Five's colors
Written and illustrated by Eiichiro Oda
While it's possible that Luffy's silhouette on the cover of volume 108 is simply a stylistic choice by Oda, it's a fact that no other character is as colorful as Luffy. Oda is also known to drop hints through colored strips on volume covers, foreshadowing major twists such as Ace's death and the future Yonko. Therefore, it may not be a stretch to assume that episode 108 could also hint at the underlying truth about Gear Five.
The possibility that Nika the Sun God is the embodiment of sunlight could ultimately explain exactly how Gear Five awakened the Iron Giant on Egghead.
More importantly, the anime also provides further evidence to support this theory. On closer inspection, one can notice that Gear Five emits a dim white light during the major battle against Kaido, especially evident when Luffy is seen in the night sky. Even in the more recent episode #1100, when Luffy transformed into Gear Five on Egghead, his hair and clothes appeared to visibly glow as they turned white.
The Ancient Kingdom's energy source may have been similar to solar energy
The possibility that Nika the Sun God is the embodiment of sunlight could ultimately explain exactly how Gear Five awakened the Iron Giant on Egghead. When the connection between Nika and the giant robot was first revealed, it also confirmed Nika's connection to the future Ancient Kingdom. If so, Nika may be the key to unlocking the mysterious power of the Ancient Kingdom which Vegapunk failed to recreate, as well as the cause of the Ancient Kingdom's fall.
In chapter #1068, Vegapunk describes his dream of creating a world with abundant energy that is accessible to everyone in the world. Vegpunk describes this energy as existing everywhere around them, waiting to be harnessed, and that the closer he gets to tapping into this hidden energy, the closer he gets to the ancient source of energy Powering the Iron Giant.
Vegapunk's description happens to match the description of solar energy, it could be the mysterious power used in the past. If so, the Sun God Nika, or rather his light could have been the source of energy that powered the entire Ancient Kingdom as well as all their weapons and inventions, serving as the sun. the second heaven that Lilith mentioned when the Straw Hats first landed on Egghead Island. This raises the possibility that Nika's defeat or capture during the Void Century could have led to the fall of the Ancient Kingdom as they lost their main source of energy and thus the ability to use their weapons during long dark night.
Overall, Gear Five and Sun God Nika still have many mysteries, many of which have yet to be officially explained. Although fans eventually accepted Official Gear Five colors, it's still difficult to guess the reason behind it, which could be something simple like depicting Nika's morality or something more related to the story. Regardless, Luffy's Gear Five continues to surprise fans with its ridiculous power, and there may be even more surprises in store for his Final Saga. A piece.
A piece available from Manga Plus and Viz Media.