Near Stonecrest fountain, you will find a NPC called Tristan. Talk to him and say “Yes”, “Yes”, “Recently”, “Digging” and you will hear a story about two men digging the ground with shovels. They found a corpse of a Seraph and head east with their caravan. Go east and follow the path that is heading to spiders. Just before you see spiders you will see a small camp with Obsidian Conclave Knights. Attack and kill about 10 of them until their commander spawns. Kill Commander Mordred and you will find a small iron key. With the key, open the chest that is located near the camp. You will find the Celestial Plate.

Quest Reward Synopsis:Ancient Celestial Plate (Reqs: 100 End, 30 Str, 30 Agi, 30 Int, 30 Wis, Seraph)