The Demon Border Guard was a demon stationed at a border of Purgatory.
An equal number of demons and angels guard the borders of Purgatory in order to preserve the balance of realms and the truce between both. Egon Spengler and Ray Stantz were unaware of this rule and breached the border while escaping from the Apple Dumpling Gang. The demon appeared at the top of a mountain and proceeded to eat Egon and Ray. However, Peter Venkman passed through the crowd and ripped the demon's guts out, effectively killing it.