Relic Location: Athena's Owl
This relic gives you treasure detection. You can find it in the debris of the Athena statue (after the cutscene where Kratos destroys it).
Relic: Grave Digger's Shovel
This relic allows you to play as Zeus in Arena combat. To get it you need to unlock everything in the Temple of Zeus.
Relic Location: King's Ring
This relic gives you 10x Red Orbs. It is found when the lava becomes gold by where Midas touched it.
How To Get Easy Red Orbs
(this works best if you have completed the games at least once)
Go to the treasures and go to combat arena than change your health and magic to infinite than in the enemies section chose any enemy you want than when you are in the battle zone press the up arrow button to activate the horn of Boreas. Just stay were you are and the enemy will come to attack you. So when they come near to you they get attacked by the horn of Boreas. They will eventually die and give out red orbs. So just keep doing this until you get enough red orb of your desire.
Relic: Aphrodite's Ambrosia
This relic gives you the Learn Might of Sparta attack. To get this relic, you have to win the "sex" minigame in Sparta three times.
Relic Location: Bonds Of Ares
This relic gives you unlimited magic. You can find it near the Death Gate in the "Domain of Death."
Relic Location: Callisto's Amulet
This relic lets you automatically complete finishing moves. You can find it on the ground after you defeat Callisto.