The Ruby Paragon can be found on a Frost Giant in The Elder Scrolls V: Dawnguard. It is one of various paragons.
Acquisition
During the quest "Touching the Sky", the Dragonborn receives an Initiate's Ewer. While inside the first room of the Inner Sanctum, there will be an altar to the left. When activated, it will remove the Initiate's Ewer and open a door, leading to a room with a Frost Giant in it and a chest containing leveled loot. Once the door is opened, the Dragonborn can take the ewer from the pedestal and run through the door before it closes.
The Paragon is part of the various loot found on the Frost Giant. Beside the north wall of the room is a second altar, which, like the first one, opens a door. this door leads to a small room with some arrows and potions as well as a second levelled chest. Once the Dragonborn has finished looting this room, the ewer can be picked up again and the player can leave the giant's room by placing the ewer on an altar beside the door the player originally came through.
Utility
The Ruby Paragon is used to activate the Paragon Socket, found on the Paragon Platform. Going into the portal will lead one to the Forgotten Vale Forest. There will be a leveled Falmer boss and a few frost trolls (they may be dead when the Dragonborn arrives, killed by the Falmer). Auriel's Shield is equipped by the Falmer. If they head west from the portal while sticking to the left, they will find a chest and a skeleton holding a few gold coins.
Quests
- Found during or after Touching the Sky.