L Lawliet

L, a renowned investigator, accepts the task of apprehending Kira, a serial killer. L becomes skeptical of Light Yagami during his inquiry and sets out to establish Light's Kira identity.

High school honors student Light consistently ranks at the top of his class. Dissatisfied with his routine life, Light discovers Ryuk's suicide letter and dispenses justice on his own. Light kills criminals to improve the world under the guise of Kira.

L. Lawliet was excellent. He is one of the best detectives in all of anime and one of the best anime strategists. He is unequaled in his ability to use scant evidence to solve extraordinarily difficult and mysterious murders. The Japanese government hired him to discover Kira's real identity and bring him to justice. As a result, L surprisingly turned into the series' main antagonist and threat to Light Yagami.

Although L. Lawliet is very smart, his messy appearance and casual attitude hide his powerful logical skills, which causes many people to question his IQ. L is incredibly thorough and analytical and has a tendency to question anything that is said to him. He is talented at tricking his adversaries and will do anything to win a case.

L's capacity for planning and data analysis allowed him to follow Light after he passed away, even though he died before the series finale. L was able to trick Light into believing he had hope when he died. That enabled Near to discover Kira's true identity and launch a pursuit for Light.

Anime: Death Note

Watch here: https://www.crunchyroll.com/series/G6QWD3EE6/death-note