Harmony holds both the shards Preservation and Ruin, and they have become intermingled. It Sazed were to die, the shard left behind would be Harmony, not Ruin and Preservation separately. It would require effort to split them back up again.
Harmony has the ability to speak and read the thoughts of any person with a Hemalurgic spike. This is shown when he speaks to Wax through his earring. He gains the ability to hear from Preservation and the ability to speak from Ruin.
|By the forgotten Gods!|
Harmony is indirectly using 瓦希黎恩·拉德利安 by way of his earring as a pawn, doing His work in the Physical Realm. He assigned Paalm, a 坎得拉, to pretend to be a human to protect Wax. Wax feels very used, especially after Paalm tears out one of her Spikes and goes insane, and Wax is deceived into killing her.
Later on, the kandra VenDell and MeLaan imply that Harmony is getting distracted and are worried that something bad is going on. Sazed confirms this to Wax during their conversation after his temporary death, showing him a red glow around the planet from some unknown hostile force.
When Wax dies, he confronts Harmony about his interference and lack of assistance. Harmony explains that he cannot always intervene because mankind would only ask for more help and always be dissatisfied. He gives Wax the option of moving on to the Beyond or going back.