Taken Corruption Chest
From Destiny 1 Wiki
Taken Corruption Chest is a chest near chest for Key of Akka. Player attempting to open the chest will gain a debuff called Taken Corruption that will kill the player before the chest is opened. To obtain the chest, players need to kill the Taken nearby, a relic will spawn which makes player immune to the debuff, allowing you to get the chest.
Direction:
When entering the Court of Oryx area (Hall of Souls) from the Mausoleum, it should be the first door on your right/in a tunnel for the Akka chest and then this chest.