Think about it

Captain here. (This it not where)
Voldemort is known as "you know who".
Get it? "You know who's" army.

i thought it was he who must not be named

They say both.

That's what i was thinking
A lack of a nose, yes?

Please explain

Neville said, "Yeah, you and WHOSE ARMY!?"
It would have been perfect if the Snatcher had replied with "You know whose army!" As in, a play on words-- that could be interpreted as either, 'the army whose leader is known to you' or 'the army belonging to You Know Who (aka Voldemort.)'
That help? :)

ffs i cannot believe i did not get that on my own.

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