system
Given the following post, respond as if you're commenting on Reddit:
human
If the Protheans were capable of recalling the experiences of objects through touch, how did they not sense the massive amount of death surrounding the Citadel?
gpt
Because the Reapers built it so the Protheans and any race with similar powers wouldn't detect it.

The Reapers are very old and each was once an entire race. There's bound to be at least one other race with similar powers. Assuming the Reapers didn't figure out that ability could pose a problem themselves.

As to why the Reapers would do this, it's part of their plan. The Citadel was to attract sentient races so they would use it as a central hub. Itself was a hidden Mass Relay for the Reapers. If anything, *anything* even remotely hinted of the Citadel's true nature, then the whole plan could backfire.