Scouts

[Asplundh]

Scouts cannot be "killed," only "captured." Only Scouts can "capture" enemy Scouts. To capture enemy Scouts, attackings Scouts must have a numerical superiority. Defending Scouts need either a numerical superiority or a defensive modifier (behind walls, for example).

If you scout/attack a city with NO walls and there are 100 level 1 enemy Scouts in the city, you need to attack with 101 level 1 Scouts of your own. In this example, you have a numerical advantage of 1 Scout, who would survive and report back to you.

In the mid to late game, it is not uncommon to find 600+ level 2 or 3 Scouts resident in an enemy city, behind a level 25 Wall. It would take 1,000+ level 2 or 3 Scouts to successfully Scout that enemy city, or you come buy an Instant Spy.