From the Wiki: "Angela is the main female protagonist of Library Of Ruina. Formerly the assistant of the Manager of Lobotomy Corporation, she is an AI who has since become the creator and director of the Library, in the hopes of ultimately becoming human and finding freedom in the outside world."

Angela is a very strict, straightforward, and logical person, as she is an AI. She does not like verbose speech and does not beat around the bush in her dialogue. Her words are sharp and concise. Despite her cold demeanor, she is a very naïve person. She has been sheltered in a laboratory for, as she was programmed to perceive it as, 1 million years. Because the white walls of the labratory was all she knew in that period of time, her social skills are clumsy, often seeming weird, cold, or offensive to others. Her naïve nature is often compared to that of a star-child, her eyes always sparkling with interest whenever people talk to her about the City outside of the laboratory and the Library. 

Other Notes:

• Examples of his voice can be found here (starts at 0:14). Here's another example of her dialogue.
• Preferably would like an Asian VA for this role, but would be fine with anyone.