Rikiel is an antagonist in JoJo's Bizarre Adventure: Stone Ocean. He is one of Dio Brando's illegitimate sons, conceived with Jonathan Joestar's stolen body, along with Ungalo, Donatello Versus, and Giorno Giovanna. This also makes him Jonathan's son, and thus Jolyne Cujoh's great great great uncle.
He inherited his father DIO's determination and hardcore actions as well as a rare trait of acknowledging a worthy opponent.
Rikiel is initially a meek youth distraught by the numerous afflictions he suffers, thus having confidence issues. When Enrico Pucci unlocks his Stand Sky High, Rikiel becomes more confident while retaining his lack of confidence, and is seen evolving into an honourable and brave fighter during his fight with Jolyne. He holds human progress in high esteem, and sees Apollo 11 as a symbol of the human growth. Rikiel is a man of honour and fights to repay his debt to Pucci, and when Jolyne defeats him, he congratulates her and reveals her details about Pucci.
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 gave out. He would attempt to take exams in school, only to suffer from his conditions, which caused him to stop attending school. 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 used his Stand powers well, weakening Jolyne's body with the use of his anatomical knowledge. Due to this knowledge, he was able to manipulate Jolyne, Ermes, and Emporio'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 that he could find her weakness by feeling her pain and attempting to conquer the odds. Jolyne, however, came out on top, dealing a massive blow to Rikiel and ensuring his death. Mortally wounded, Rikiel used his own Stand on himself, removing his ability to feel 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 characterise 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.