The Lorestones in Gorguath

From Destructoid:

Kingdoms of Amalur: Reckoning demo item unlocks for Mass Effect 3:

• Reckoner Knight Armor: This armor will maximize damage done in close-quarters combat while a beefed–up power cell feeds energy into weapon systems to increase projectile velocity.
• The Chakram Launcher: This weapon uses a fabricator to manufacture lightweight, explosive ammunition discs. This weapon is earned after completing the Reckoning demo and watching the trailer at the end.

Mass Effect 3 demo item unlocks for Kingdoms of Amalur: Reckoning:

• N7 Armor: Players can unlock special armor inspired by Commander Shepard’s iconic N7 battle armor including Helm, Cuirass, Gauntlets, Chausses and Greaves.
• Onmiblade Daggers: A holographic blade stemming from Commander Shepard’s Omni-Tool, the Omni-blade allows players to stab enemies in close combat. Once players install and play the Mass Effect 3 demo, they will unlock the daggers.

Kingdoms of Amalur: Reckoning demo item unlocks for Kingdoms of Amalur: Reckoning:

• Twist of Fate Card: This card boosts the player’s ice resistance and is immediately unlocked when he or she activates the Reckoning demo using his or her Origin account.
• Twinned Souls Chakram: A unique weapon that damages enemies while boosting player health and mana in Reckoning.
• The Infernal Helm: Unlocked after completing the Reckoning Tutorial Mode, this protective helmet increases players’ fire damage throughout Amalur.

I never looked for it in the demo (though Paul Z says its there), but it is definitely in the main game, outside the building just beyond the well in the center of town, where a group of people are gathered around the wounded Fae when you first arrive.

I had the following items inside:

• Twinned Souls
• Shepard's Cuirass
• Shepard's Chausses
• Shepard's Helm
• Shepard's Gauntlets
• Shepard's Greaves

All of the "Shepard's" gear requires Might 3 to wear. Looting it all from the chest unlocked a new destiny for me. I don't know if it would be in there for everyone, or just for those who pre-ordered Mass Effect 3 like I did.