Joyboy is a title, it's not a name, it is a title.
One thing people don't know is this, DF are named based on a scheme known as Onomatopoeia.
An onomatopoeia is the word for a sound something makes.
Oda names fruits based on the sounds they're associated with 9/10 times.
Examples:
- "Guragura" (グラグラ/ぐらぐら?) is a Japanese onomatopoeia describing loose, irregular/unstable movements (shaking, wobbling, etc.), such as the shaking during an earthquake.
- Gorogoro (ごろごろ・ゴロゴロ?) is a Japanese onomatopoeia for the rumbling of thunder.
- Meramera (メラメラ/めらめら?) is the Japanese onomatopoeia for something flaring up/bursting into flames.
Oda didn't name Whitebeard's fruit the Earthquake Earthquake no Mi, but instead named it the sound an Earthquake makes.
Oda didn't name Enel's fruit Lightening Lightening no Mi, but the sound Lightening makes which is thunder, he didn't even name it thunder thunder no Mi, but the sound it makes.
Oda didn't even name Ace's fruit fire fire no mi, but the sound that fire makes. If Oda named it Fire FIre no Mi, it should be called "Hi Hi no Mi".
Oda
almost NEVER names a fruit by what it literally is, he always names it by the sound it makes 9/10 times or by a quality that thing has.
If you're a blade human, Oda names your fruit Supa Supa no Mi which is the sound that blades make when they slash or cut things.
Nika (ニカ?), a nonstandard Japanese onomatopoeia for "smiling" or "grinning" - the sound a smile makes.
Nika is the sound for smiling in Japanese, how does smiling have a sound? Ask the Japanese about their culture, and how it makes sense, but that's just it.
Nika is a title, and it is the same thing as Joyboy. Nika means smile while Joyboy pretty much means happy person, they're the same thing.
When Oden returned to Wano, he said he'll be opening the border for Joyboy despite the fact the first Joyboy is dead. It means Joyboy is a title. Joyboy is a title for whoever eats the Nika Nika no Mi.
Nika/Joyboy is also a god in the same way Buddha is a god.
In conclusion, Nika = Joyboy, and it's a title/name of a deity and the sound of smiling or description of smiling. Luffy is the current Joyboy/Nika, we will probably know the name of the previous Joyboy/Nika once Oda gives us more details on the Ancient Kingdom and lores.
