The last in the "Warlock Spells" mini-series, Ritual of Souls is a spell everyone can love. Why? Healthstones! And who doesn't love a nice, refreshing healthstone every now and then? The fact that it's a reduced shard cost for the warlock just makes the warlock happy.
This spell is only usable out of combat. The warlock starts the spell and a small altar drops out of the sky. Two people in the party/raid assist, and the altar disappears, to be replaced by a red crystal. One shard is consumed, and up to 10 healthstones can be pulled out of the crystal for the next 5 minutes. The healthstones will be just like getting one from the warlock made one-at-a-time, benefiting from the Improved Healthstone talent. As an added bonus, the red crystal that spawns will dispense healthstones for a full 5 minutes, whether you are in combat or not. So before a long fight, warlocks can drop one of these, give out healthstones, and if someone uses their healthstone during combat they can pick up another one and use it after the 2 minute cool down on healthstones has expired.