The Last Faith

You need to finish Lady Annika's quest to be able to buy the second skin mask from the Veiled Maiden to get both of Esk's eyes. You also can't get them until you get the Celestial Larva (double jump). The second skin mask will show you the hidden ghost and area to get the eyes. Both eyes are needed for the true ending. I waited to get both eyes together until after I did the first two endings. See Embrace the Cosmic Voice (70G) for more information.

Esk's right eye is in Moonshade Lake. This area is in the southern part of the frozen caverns in the Damned Ruins of the Osseus Fortress. You will need to fight and kill the Starlight Beast of Illygarth to be able to get to the area its in.

Esk's left eye is directly west of the big mirror you use to teleport to fight Yegor and Leena. You will have to fight and kill the Harbinger of Nightmare.

Both of these bosses you kill have achievements also.

All credit goes to lilfarmboi. Please give them a like.