Eric Pekka was an 18-year-old Finnish male with a relatively ordinary appearance: tall and slim, pale-skinned, with short light-brown hair, slickand a typically neutral or serious expression. He dressed casually, often in dark clothing, blending in with other students.

Psychologically, he was described as introverted, withdrawn, and socially isolated. He showed signs of deep resentment, low empathy, and a strong sense of alienation. He expressed nihilistic and misanthropic views online.