Quick Scoop: Why does Weather Report have a Joestar birthmark?

The short version: Weather Report has a Joestar birthmark because his twin brother, Enrico Pucci, fuses with the Green Baby created from DIO’s bone (which comes from Jonathan Joestar’s body), turning Pucci into a “Joestar by bloodline extension” — and that supernatural Joestar connection spreads to Weather as well.

The in‑story explanation (Part 6, Stone Ocean)

In JoJo’s Bizarre Adventure: Stone Ocean , the Joestar birthmark is tied to the Joestar bloodline and to the bizarre “heritage” mechanics Araki uses across the series.

Here’s how it plays out in Part 6:

  1. DIO’s bone → Green Baby
    • A bone from DIO is used in a ritual and produces the Green Baby.
 * DIO’s body originally belonged to Jonathan Joestar from the neck down, so his bone carries Joestar DNA.
  1. Green Baby → Pucci + Joestar mark
    • Pucci follows DIO’s “Heaven” plan and fuses with the Green Baby, evolving his Stand and his very being.
 * Because the Green Baby is born from Jonathan/DIO’s body, it bears the Joestar birthmark and passes that mark to Pucci when he absorbs it.
  1. Pucci → Weather Report
    • Weather Report is Pucci’s twin brother (Domenico Pucci), so they share blood.
 * In JoJo, bloodline‑based phenomena often propagate through relatives (for example, Stands awakening in the Joestars because of DIO, or Trish sensing Diavolo).

 * Once Pucci takes on the Joestar birthmark through the Green Baby, that Joestar “heritage effect” extends to Weather as well, so the same star symbol appears on him.

So Weather doesn’t start as a Joestar; he becomes linked to the Joestar bloodline after Pucci’s fusion with the Green Baby.

In other words:
Jonathan’s body → DIO → DIO’s bone → Green Baby → Pucci → Weather.

Why this fits JoJo’s recurring themes

Araki has used similar logic before:

  • When DIO gained his Stand with Jonathan’s body, other Joestars (like Joseph and Jotaro) awakened Stands because they shared blood.
  • Trish and Diavolo sharing a psychic link, and DIO sensing Joestars, reinforce the idea that supernatural effects can echo along bloodlines in strange ways.

Weather’s birthmark is another instance of JoJo’s heritage and bloodline motif, turned up to eleven via DIO’s Heaven plan.

Fan theories vs. clarified answer

For a long time, fans speculated that Weather might secretly be a “real” Joestar or have some hidden lineage.

Popular fan angles included:

  • Weather as an “unrevealed Joestar branch”
  • The birthmark as a hint at a much bigger family twist
  • A symbolic rather than literal Joestar connection

Later explanations in official‑adjacent discussions and fan Q&A style breakdowns converged on the Green Baby/Pucci route as the concrete mechanism: fusion with a Joestar‑origin creature makes Pucci effectively part of the Joestar line, and that spreads to his twin brother Weather.

Mini FAQ

Is Weather Report “officially” a Joestar?
He is not born a Joestar; he becomes Joestar‑linked because his twin brother fuses with a being made from Jonathan/DIO’s body, gaining the Joestar birthmark that carries over to Weather.

Why does JoJo do this kind of thing so often?
Because JoJo leans heavily on inherited fate, bloodline echoes, and supernatural genetics, so the story often uses DNA and ancestry as a bridge for powers and symbols like the birthmark.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.