In the world of One Piece, many characters have different heights and weights, so identifying these characters by just their silhouette is actually an easy task. However, the One Piece silhouettes suffer from a very strange problem that has persisted throughout the entire story.
Specifically, the silhouettes of new One Piece characters tend to not resemble the character designs when they are officially revealed. In fact, this difference is so large and noticeable that the One Piece community constantly creates memes about this very issue.
One Piece character silhouettes look nothing like their final designs
In One Piece, often before a character is officially introduced, other characters and flashbacks will briefly mention them, alluding to their existence. For example, at the end of the Enies Lobby arc, Garp revealed the existence of the Four Emperors. Although Shanks and Whitebeard are fully shown, mainly because they were introduced in the story at this point, the remaining two Yonko Big Mom and especially Kaido are only shown in silhouette.
When Kaido officially appeared, this figure looked nothing like the captain of the Beast Pirates. This silhouette, instead of showing the giant, muscular monster that is Kaido, shows a short and seemingly unthreatening person. In addition, this phenomenon has happened to many other mysterious characters of One Piece, such as prince Loki.
Silhouettes in One Piece are mostly unfinished designs
First of all, one of the main reasons why these silhouettes don't look like the final design, is because Oda hasn't completely decided on his design for these characters yet. The characters in One Piece have strange body types and odd proportions, meaning they would be instantly recognizable from a silhouette.
However, if the character is not yet finished, it is better to use a simple silhouette so as not to distract the viewer from the finished designs of One Piece. Otherwise, if Oda is committed to designing the characters from the beginning and providing an accurate silhouette, it will be difficult to go back and redesign the character's complete look.
Next, the mysterious silhouettes of One Piece characters help retain some mystery and suspense for their final reveal. If Kaido only seemed like a pale shadow of himself in Garp's story, it would detract from his epic introduction in the post-time skip era. While the silhouette doesn't need to be wildly different to achieve this effect, it should at least be extremely simple so as not to draw comparisons to the final design.
