Alchemy is the name given by non-Eldan races to a form of science that manipulates primal power through biochemical means - usually by blending certain elements, biological matter, even tangible energies to create elixirs and potions that can be consumed by living creatures. The practice of alchemy occurs in many galactic cultures, most notably among the Mordesh of Grismara, who literally wear their alchemical prowess on their sleeves in the form of the Vitalus serum.
Other infamous practitioners include underworld organizations like the Darkspur Cartel or Nexus cultures such and the giant Osun. Though there is not necessarily anything inherently "evil" about the practice of alchemy, it does have negative connotations to many.
The school of alchemy dedicated to defeating the ultimate enemy - death itself - is known as necro-alchemy. The most commonly encountered forms of necro-alchemy are simply devoted to reanimating dead tissue to create what are colloquially known as "risen" or "zombies," and such necro-alchemists are sometimes referred to inaccurately as "necromancers."
More ambitious necro-alchemists have focused on actually restoring true life to the dead, albeit with no confirmed successes. Such individuals are often unbalanced and obsessed, and should generally be considered dangerous to the living.
"Risen" is the name commonly given to organic creatures that have died and been reanimated through some form of necro-alchemy be it Moodie necromancy or Eldan super-science. Though the moniker is imprecise, scans show that all risen creatures do have some commonalities - including evidence of primal life and other primal energy infused into their bodies at the molecular level.
Although not as famous (or infamous) as the Mordesh alchemists of the Exile Academy of Science, the Royal Collegium has its share of alchemical experts and primal manipulators. Dominion alchemists are iconoclastic individualists not organized into a guild or faction of their own - not since the Imperial Alchemical brotherhood nearly turned the atmosphere of Cassus into a toxic soup during the reign of Seraphel the Builder. Rather, they tend to work within different organizations as experts or project heads. That said, the Dominion Research and Experimentation Division (DRED) probably employs more alchemical researchers than any other group in the Dominion.