Yusaku Fujiki

Yusaku Fujiki is the main protagonist of the anime Yu-Gi-Oh! VRAINS (2017–2019).

He is a highly intelligent, reclusive high-school student and skilled hacker who lives a double life under the alias Playmaker, the top duelist in the virtual reality network called LINK VRAINS.

Key traits:

• Extremely calm, analytical, and emotionally reserved (often described as "cold" or socially detached)
• A genius-level duelist who specializes in Cyberse monsters and Link Summoning
• Driven by a traumatic past connected to the Lost Incident (also called the Hanoi Project), which gives him a strong personal motivation throughout the series
• Prefers to work alone and initially shows little interest in making friends, though he gradually develops bonds with certain people

In short: a brilliant, stoic, lone-wolf hacker-duelist with a tragic backstory who becomes the central figure fighting against the organization responsible for his childhood trauma.