Simon Blackquill / Jin Yuugami

Age: 28
Gender: Male
Occupation: Prosecutor / Prisoner

Main prosecutor of AA5.

Personality: Simon is gruff and condescending with a dark sense of humor.  He uses his knowledge of psychology and generally dismissive personality to manipulate other people (most notably the judge).

Misc Facts: Simon was sent to prison on a murder charge, but because this is the world of Ace Attorney, he somehow still gets to be a prosecutor.  He often talks about his fellow inmates, and appears in court wearing handcuffs.

In the Japanese version, Simon refers to his opponents by picking out one kanji of their name. 

Friends and Family
: Works with Detective Fulbright, and his sister is Aura Blackquill.  He also has a hawk, named Gin (Japanese version), who lives in the courthouse and acts as his partner when he's prosecuting.

Name Origin:
English: His surname is a reference to his hawk motif.

Japanese: The kanji in his surname mean "god of dusk." It's also a play on yugami, referring to his nickname in the AA law enforcement community, "a distortion of the law" (being a prisoner who prosecutes).  The kanji in his given name means "swift," though it shares a pronunciation with "blade," his weapon of choice.

Background: Seven years ago, Simon was convicted of murder (he confessed).  

Spoiler: AA5-5
But before that, Simon was a prosecutor and a student of psychology. He often visited the GYAXA space center, not only for his sister, Aura, but Metis, who he respected as a mentor. He was also fond of Athena, who confessed to him that she felt neglected by her mother.

The morning of the launch, Simon came to the center intending to speak to Metis regarding Athena. When he entered the robotics lab, he found Metis dead at the repair chair, and Athena covered in blood and holding a knife. Afraid that the unthinkable had happened, Simon dismantled witness Ponco and snuck her and Athena out of the lab. He bloodied his sword and confessed to the murder to prevent Athena from being suspected. It wasn't until afterward, when the center was bombed and its launch nearly thwarted, that Simon realized the Phantom was behind it all.

For the next seven years, Simon did what he could (behind bars) to discover the Phantom's identity. With the return of Phoenix Wright to law, Edgeworth gained confidence that the case could finally be solved, and thus grant Simon permission to take up the mantle of prosecutor in the hopes of clearing his name.