|Stand||Scary Monsters (with the Left Eye)|
|Date of Death||January 18, 1891|
|Hair Color||Blonde (EOH)|
|Eye Color||Cyan (EOH)|
Unnamed Mother (Surname Brando) (Deceased)
Unnamed 80 year-old Wife (Deceased)
|Manga Debut||SBR Vol. 1 Ch. 1|
The Steel Ball Run: Press Conference
|Final Appearance||SBR Vol. 19 Ch. 76|
D4C (Dirty Deeds Done Dirt Cheap) (9)
|Game Debut||Jojo's Bizarre Adventure: Eyes of Heaven|
|Seiyuu||Masayuki Katou (voiced comics)|
Takehito Koyasu (All Star Battle and Eyes of Heaven)
Diego is a young man of below-average height and slim to medium build. He has light hair, dark eyebrows, and light, bold eyes.
He commonly wears an equestrian helmet with the letters "D", "I" and "O" mounted on bending pins emerging from a small ribbon tied at its front; a turtleneck jumper patterned a diagonal grid; light, mid-forearm-length gloves; light, wide-legged breeches; and tall, dark riding boots.
Although his mother raised him with much love, he had a very hard life growing up in poor conditions they were forced to live in, resulting in his cold-heartedness – it is said that he will virtually do anything to win. At the age of 20, Diego married a rich 83 year-old woman who died six months later, enabling Diego to inherit her wealth. This led to speculations that he murdered her.
- Main article: Scary Monsters
Diego first turned into a dinosaur after he along with a number of villagers were controlled by Dr. Ferdinand to steal the left eye of Jesus Christ from Johnny and Gyro.
After he was defeated, Diego stole the Corpse Part and it fused with his left eye, giving him the ability to turn himself into a dinosaur. 
HistorySince he was a child, Diego had a talent for relating to horses - even seemingly untameable ones would allow themselves be handled by him.
Diego's parents were financially weak and attempted to dispose of him as a baby. However, his mother felt guilty, and risked her own life to save him from drowning, upon which his alcoholic father left them both. His mother changed her surname to "Brando" and became employed by a farm, but she and Diego lived in poverty in the stables.
Five years later, the man that had arranged her employment demanded sexual favors from her, and upon her refusal, sabotaged their means to get food. No matter how hard the times he and his mother fell on, she refused to discard of what little dignity they had left – she taught Diego that eating out of shoes due to lack of proper dishes was unacceptable.
Partly from her example, Diego developed a strong sense of pride. . Another year later his young mother died of the tetanus infection, which Diego (at the time 6 years old) believes to be a result from the humiliation they had to suffer. The boy grew up resenting everyone who abandoned them and swore to himself to get revenge against the man who had harassed his mother.
Steel Ball Run race
After he loses the first stage of the Steel Ball Run to Gyro Zeppeli, he becomes irritated and considers Gyro his personal enemy from that point onwards.
At a later point of the race, Diego meets Gyro and Johnny again in a small village in the mountains. He appears to be friendly, but just as the two heroes think he won't harm them, he suddenly transforms into a Deinonychus and attacks them.
It turns out that the meeting was a trap set up by the bounty hunter Dr. Ferdinand. Ferdinand's Stand power can turn living beings into dinosaurs. He uses this ability to create dinosaur "bodyguards" in his hunt of the Corpse Parts. Even Diego was turned into one of his soldiers when he was attacked by him earlier.
Gyro manages to defeat Dr. Ferdinand by fusing with one of the Turbo eyes that Ferdinand possessed, receiving the Stand ability "Scan".
Even though Ferdinand was killed and all his dinosaur minions turned back into humans, Diego escaped with the second Turbo Eye, transferring to him Ferdinand's stand power and the ability to turn into a Raptor when he wants, though he initially can't control it very well.
Allying with Valentine
Later in the series, after losing another round to Gyro, he joins Funny Valentine, the president of the United States, who is searching for the body parts of "The Saint", which are said to grant great powers. By doing so, Diego hoped to find a way of defeating Gyro.
During the 8th round, Diego turned against Valentine, but was quickly defeated by his Stand, Dirty Deeds Done Dirt Cheap, and had the Corpse's Eye taken from him.
Diego's life ends after being ejected from and run over by Valentine's train and is consequently torn in half; although he is soon succeeded by a Diego from a neighbouring universe, retrieved by Valentine, to track down Johnny.
Diego appears on the Steel Ball Run themed stage, along with Johnny Joestar and Gyro Zeppeli. Where Diego can be seen ahead both of them (similiar to the end of the competition's 3rd race).
Diego was one of the first characters confirmed to be playable in the game (alongside Jotaro, PART II Joseph, Kakyoin, Josuke and Stroheim). He also appears as the solo final boss for the game's demo.
Several of his basic attacks includes moves done in his battle against Funny Valentine, such as cuts done by his bare hands. Using his stand Scary Monsters Diego can summon some dinosaurs and make them attack his opponents. Much like Johnny and Gyro did in All-Star Battle, Diego can ride his horse, Silver Bullet, in order to use different moves or move quicker on around the stage. Diego can also transform himself into a dinosaur to attack the opponent with bites, dash attack and heavy stomps.
Since Diego can be considered Dio's alternate counterpart, he's voiced by Tahekito Koyasu.
- As a 5-year old boy, he resembles the adult Giorno Giovanna; his hair in curly bangs and a small tail at the back.
Similarities to Dio Brando
- A fondness towards his mother (likely the only person he truly respects) and an uncaring, alcoholic father.
- Unscrupulousness and a wish to dominate.
- Marriage to a woman of considerable age who fell in love with him, and it is rumored, he murdered (perhaps a reference to Enya Geil (OVA) who died by his hand).
- Both attempted to unjustly acquire inheritance money at the beginning of or prior to the start of the story (Dio tried to claim the Joestar family fortune while Diego successfully claimed his elderly wife's after her demise).
- A physical ascension to a superhuman form (as original Dio became a Vampire, Diego gains the ability to transform into a dinosaur) with the byproduct of another person.
- When Diego was put into submission by Hot Pants, he "kissed" Hot Pants to force her to release him and the sound effect that appeared in the panel was the same to Dio's kiss with Erina.
- Being cut in half (Dio was cut vertically in half by Jonathan and Diego was cut horizontally in half by a train), both surviving in one way or another.
- Beheaded shortly after his defeat.
- Diego's horse Silver Bullet may be a reference to silver bullets, a form of ammunition used in European myths that have the capacity to kill supernatural beings, more famously vampires or werewolves.
- The final antagonist Jonathan ("Johnny") Joestar has to face, and defeated by a different person (Dio by Jotaro, Diego by Lucy).
- Inhibited by a leg injury, ultimately leading to death.
- ↑ SBR Chapter 64: Chocolate Disco (1)
- ↑ SBR Chapter 12: 1st Stage Disqualified From Victory
- ↑ SBR Chapter 1: The Steel Ball Run: Press Conference
- ↑ SBR Chapter 30: Scary Monsters (3)