A shaman is defined as a person who acts as intermediary between the natural and supernatural worlds, using magic to cure illness, foretell the future, control spiritual forces, etc.Mr. Ellis created/redesigned characters that functioned as shaman in his books (like Nate Grey in the Counter X series, the Doctor from Stormwatch/Authority, and Century Babies in Planetary).
Nate Grey functioned as intermediary between the 616 reality and parallel as lower and upper realities, and maintained a multiversal balance. Upper realities were virtual utopias like the Deva Realm from the 6 desire realms in Buddhism. The lower realities were hellish planes like the Preta and Naraku realms.
The Doctor (all iterations) and the Century Babies functioned as mediums for humanity and Gaia (the Earth itself) and maintained harmonic balance.

He also introduced ideas like:

“Down there are people called ayahuasqueros. Tribal doctors, mystics, medicine men. They take this stuff called ayahuasca, this awful mush they brew up out of vines and stuff. It’s a psychedelic. They hallucinate all over the place — but it’s their belief that the visions are actually another dimension. When you ask them why they take it, they say it’s for working with the ancestors. They’re necronauts. They travel in the place of the dead. And what they bring back are messages from the afterlife.”
– Sam Wilson (in Ultimate Nightmare)

“You are aware through esoteric scientific research conducted by many people over the Twentieth Century. that souls do not die. Souls are some form of electromagnetic field that continue to inhabit the body after death. Bones, crackling with strange and imperceptible energetic activity. And we buried them. Are they still aware? Can the dead still perceive we don’t yet know. Is that happens? We lay in the dirt, still somehow aware of being in there? And gravity draws us into the earth. And plants grow. Ayahuasca. Peyote. Psylocibin. Stropharia Cubensis. The drugs. Yes, historically, we consider them shamanic drugs, and they were overlaid with ritual and religion and the other crap of archaic societies. But all societies had their speakers to the dead and their oracles who looked into other places. In legend, the Oracle at Delphi stood at a pool and inhaled its vapor, the pneuma, to oraculate. It was recently found that a vent beneath the pool expressed ethylene, a hydrocarbon gas that creates an euphoric derangement, into the water. Ethylene, the pneuma, is a plant hormone. The dead lay in the ground, their souls oiling out from their bones, into the earth, into roots… that effervesced into the clouds that the oracle inhaled to see new worlds. Into the plants that our speakers to the dead ingested to do their business.
– Melanctha (in Planetary)

“You’re a machine. I’m a machine. Our parts are made out of water and meat and minerals, but we’re walking pieces of engineering. Everything’s a machine. Plants, everything. When we eat a plant, we disassemble it, junk what we don’t want and plug the parts we need into our machine. What if these jungle drugs are machines we can ride?”
– Sam Wilson (in Ultimate Nightmare)

His ideas lead me to look at shamanism, the soul, death and planes of existence, from a different angle. I would love to read an Ellis book where he jumps head first into this theme and runs wild with it in a similar manner to his Crooked Little Vein novel.

Images courtesy of Ben Templesmith and Freak Angels.Warren Ellis’ images courtesy of Warren Ellis’ Official Livejournal.