Aegis of the Immortal:

The Aegis of the Immortal is a Roshan drop that lets a hero return to life after being killed. It is one of Dota 2’s most important objectives because it can give a team a second chance to hold a fight, push high ground, or escape after a key death. In most matches, securing the Aegis is a major power spike and often changes how both teams position around Roshan and major teamfights.