Final answer:
The technique that uses a fictitious individual with detailed demographics to characterize the typical user in software development is called a User Persona.
Step-by-step explanation:
The software development technique that creates a fictitious individual with detailed demographics to characterize the typical user is known as a User Persona. A user persona is a semi-fictional character based on the targeted user group for a product, which helps developers and designers to understand the users' needs, experiences, behaviors, and goals. This technique is utilized to guide decisions about product features, interactions, and visual design with the user in mind.