Originally Posted by soran
these posts are so annoying to read
Except you can't really deny the validity of Louis's point. To say captains should be able to sense them ignores the fact that the captains couldn't find the Vizard, Fullbringers, or the Ishidas(nor could Ishida, who can instantly tell who had spiritual power, failed to notice his father). Despite Soul Society magically being able to detect the moment and type of beings that appeared the second Yammy, Grimmjow, and Luppi appeared in the Living World, they were woefully ignorant about their missing Substitute Shinigami's location or the Vizard. Aizen had to go looking for Vasto Lorde and was still gathering them.
They seem to only be able to find people in areas they specifically control like Seireitei or Las Noches. Even then, they can only detect them upon entry, passing through a barrier(who the Vandenreich can bypass using the "shadow"). They have no idea where they are specifically inside the location (hence why Ichigo's group got so far).
Basically as long as they stayed out of Seireitei, there's no reason to know they exist. Soul Society knows nothing about who is in Hueco Mundo(e.g. the Espada) and very little about the Living World(e.g. Fullbringers, Vizard). It's painfully easy to hide from them.