Orpheus

Orpheus is the son of the Muse Calliope and a mortal. Calliope the group came into being through his work.

Calliope
Orpheus created Calliope, for which reason the Namesakes call him The Founder.

We know that Orpheus is currently in a very weak form, being unable to manifest safely to continue the work of Calliope without assistance. He needs the help of the Cheshire Cats like Chester, Jasper, and Whisper (well, all of them are the same Cat, really) to be his voice at meetings. Both the Rippers and the Namesakes are bitterly at loggerheads with each other, and until this resolves...being in hiding is probably the safest.

Agents of Orpheus:
Orpheus has a few allies who answer directly:

Wendy Shepard

Banshee

Bog

Cheshire Cats (when asked)

Indirect Agents:
Indirectly, Orpheus' allies are:

Jason, who figured out for himself that Wendy and Bog are working for Orpheus and said nothing to betray them.

Vanessa (indirectly; as she's Banshee's reluctant ally for now)

Dro the Earth-Giant. He makes use of the powers Orpheus grants him to protect the hill Calliope rests on.