I will throw my hat into the ring with Ezekiel. He is a cleric of Groetus who channels negative energy. I know that this is not optimal for healing purposes but who ever heard of a prophet of doom that was focused on healing?
Ezekiel is motivated by an omen he in a blacksmith's shop. The blacksmith could not light a fire in his forge and loudly complained that, if this continued, it would be the end of his livelihood. Even when lamp oil was put into the forge it failed to burn. Ezekiel saw this as foreshadowing of End. And when the call went out for volunteers to retrieve fire from the Everflame, Ezekiel was consumed with the need to make the journey and see if interpreted the omen correctly.
EDIT:
I just saw the feat Versatile Channeler. This might be away to make him viable as a healer. I just need to work on a rationale as to why a cleric of Groetus would want to be one.