An Altar was a structure in Legacy. It consisted of 2 stairways, a Shadow Pad in between them and a drop-off point in the center of the upper floor.
Purpose[]
Before the V32 patch, Altars served as a drop-off location for the OP Buff. The carrier had to deliver the buff to the enemy Altar to trigger the effects of the buff for all of his teammates, or to the allied Altar to restore all friendly Inhibitors.
Because the V32 patch has made it so the buff activates immediately after killing the Guardian, the Altars served no purpose since.
Altars are not featured in Monolith.