Mangetsu has a crush for Arrow?!

No, I don't think Mangetsu has a crush for Arrow, but I had to pick the third choice in this specific scene just to make Ringo make everyone laugh a bit. Admittedly though, it's kind of scary to think that your life has been monitored all day long without you even realizing it was happening.
How did he manage to do that considering Arrow was around powerful entities that should've been able to detect Mangetsu spying? (Like Aion for example)
He seems to be the most mysterious character so far, way more than the relatively straightforward Iron Mask of which we know the objectives of.