Border Guard
From The Heroes of Might and Magic III wiki
Adventure map objects that can't be passed until you've been to the correct Keymaster's Tent. There are eight colors of of Border Guards-- Red, Green, Light Blue, Dark Blue, Yellow/Brown, Purple, White and Black-- and you can't pass until you've been to a Keymaster's Tent of the same color. When you wish to pass, the guards are lowered, and anyone can pass after that.
