High Priestess' royal duties

Staving off demons and aberrations from the kingdom is one of the services the High Priestess have to perform once each New Moon. In her cerimonial garments, she descends to a portal where the ley lines connect and a battle against the invading horrors from other worlds awaits. 

When the priestess comes back from the portal, most of the times she's exhausted and her clothes are ruined... However, the whole congregation can see her reassuring smile and cheer for her victory.

She succeeded once again and our realm is safe!

But well... It's weird how our guardian looks so eager for those battles. What's exactly happening each time she crosses the portal?