The Man in The Wall

"He's watching" - Rell

A sentient emanation of the Void named "The Man in The Wall" is a mysterious being that mainly appears in Chains of Harrow quest, but also makes appearance in The War Within speaking through Tenno after each of their reply choice and sometimes appearing in Tenno's Orbiter performing certain activities and taking form of the Operator.

When approached, it will say "Hey kiddo" most of the time and will remain until player has reloaded the instance (either by re-logging into the game or going into a mission).

Trivia

 * Other titles are "The Lidless Eye" and "The Indifference", given by Red Veil.
 * Rell's understanding of The Man In the Wall's presence likely came from his mental disorders as the other Tenno who act indifferent appear to not understand about it even after being controlled by it.
 * It's noted that The Man in The Wall existed before time, suggesting Void itself is a natural construct and not a product of Orokin.