L Dies — Light's Expression
L collapses while Light holds him, watching his rival and only intellectual equal die while maintaining a perfect facade.
Why it hits: Light's expression as L dies — not triumph, not grief, nothing — is the most chilling image in the series.
Rem Kills L and Watari for Misa
The Shinigami Rem writes L's name to protect Misa, and is destroyed for it.
Why it hits: A supernatural being dying out of love for a human rewrites everything the show established about Shinigami.
Higuchi Sees Ryuk
A cornered Kira successor is told to look up and sees the Shinigami — his first glimpse of what the Note truly is.
Why it hits: The reveal of supernatural horror to someone who thought they were running a scheme is viscerally effective.