How to Unlock all the Characters Bios in Batman: Arkham knight

Batman: Arkham Knight unlocks most of the characters as you progress in game. But there might be a chance that you miss some hidden characters bio which you don't get in normal gameplay. So here is the list of all the characters including hidden, DLC's and their bio unlock locations in detail.

Hint: 
Press Tab to enter the map screen and further press (-) to navigate to Character Bios screen. Here you can select and read them any time you want.

Characters available From the Start:

• Bruce Wayne
• Batman 

Characters available in Chapter 1: It’s Going To Be A Long Night 

• Gordon  
• Aaron Cash   
• Poison Ivy 0 
• Jack Ryder  
• Oracle 

Characters available in Chapter 2: Patience Is A Virtue

• Alfred
• Arkham Knight
• The Joker
• Scarecrow

Characters available in Chapter 3: It Is Dangerous Out There

• Catwoman
• Lucius Fox
• Nightwing
• Penguin
• Riddler

Characters available in Chapter 4 & 5:

• Simon Stagg - Prey That No Longer Fears You
• Robin - Tonight Ends With Gotham’s Fall

Characters available in Chapter 6: Some Kind of Bat Trick

• Harley Quinn
• Christina Bell
• Albert King
• Henry Adams
• Jason Todd
• Johnny Charisma

Characters available in Final Chapter 9: The Die Is Cast

• Deacon Blackfire
• Deathstroke
• Red Hood
• Martha Wayne & Thomas Wayne - when you remember them before the Scarecrow boss fight
• Vicki Vale - when you see her in the ending cutscene

Characters available in Most Wanted Missions:

• Professor Pyg - The Perfect Crime
• Fire Chief - The Line of Duty
• Azrael - Heir to the Cowl
• Hush - Friend in Need
• Kirk And Francine Langstrom - Creature of the Night
• Man-Bat - Creature of the Night
• Firefly - Gotham on Fire
• Two-Face - Two-Faced Bandit

Characters available in DLC

• Batgirl - Joining your mission can come with a cost, this empty reminder shows just what she lost.(Also in First DLC)

Tip: Additional information is unlocked as Batman encounters important characters during his adventure in the main story and side missions.