|Namesake||Sonia Rykiel (French Fashion designer)|
|Hair Color||Dark Black|
|Relatives||Dio Brando (father)|
Dario Brando (grandfather)
Dio Brando's mother (grandmother)
Jonathan Joestar (biological father)
George Joestar II (biological half-brother)
Donatello Versus (half-brother)
Giorno Giovanna (half-brother)
|Manga Debut||Vol. 76 Ch. 705|
Long Time No See, Romeo…
|Final Appearance||Vol. 76 Ch. 711|
Sky High (6)
Prior to meeting Enrico Pucci and obtaining a stand, Rikiel suffered from what seemed to be constant panic attacks: his eyelids constantly fell and his knees went bad. He would attempt to take exams in school, only to suffer from his conditions, and would stop attending school because of them. These conditions were so severe that he wasn't even able to drive a car, and this dramatically decreased his self-confidence.
Upon meeting Pucci and obtaining his stand, Rikiel instantly became more confident, going as far as to present himself to the heroes believing he could easily defeat them. Though new to his abilities, Rikiel demonstrated a fine use of his powers, weakening Jolyne Cujoh's body enough that he could fight her easily, and demonstrating enough anatomical knowledge such that he was able to manipulate Jolyne, Ermes Costello, and Emporio Alnino's conditions to deal various biological setbacks to them.
It was when Jolyne set herself on fire to counter the effect of Rikiel's stand that he began to lose confidence, forcing Rikiel to set himself ablaze as well, believing in finding her weakness by obtaining her pain and attempted to conquer the odds. Jolyne, however, came out on top, dealing a massive blow to Rikiel and crippling and ensuring his death. Mortally wounded, Rikiel used his own stand on himself, removing his sense of pain and holding onto Jolyne to force his stand into a last-ditch effort to kill her. However, she allowed this and continued her attack, coincidentally using his hand to block his ability to sap her heat. Defeated, Rikiel reflects on his past and the coincidence that was able to characterize his defeat and Pucci's power, and reveals that Weather Report is actually Pucci's younger twin brother. Just as he reveals this, however, he is finally silenced by Ermes.