SHADE;
These are your 'common' zombies - what happens when the Darkness reanimates an already dead body. They require only a trace amount of energy to create, and as such, are of the weakest sort. While they do not feel pain, hunger, or similar traits of living mechs - their intelligence is crude at best, and often they can only be tasked with a single, simple instruction. Aside from the already distilled 'instinct' to kill anything living they come across. Some have displayed an urge to consume the metal of others; this is thought to be an attempt to assimilate the metal, and repair their own damage. It is also rather useless, as such is impossible - no Shade has displayed any sort of regenerative capability, unless elevated to the status of an Echo.
While they can endure shots that would kill a normal mech - due to being already dead - their armor is rather weak, even compared to another dead chassis. The easiest way to kill them is blow their heads off, or their torsos apart. Cut them in half, remove enough climbs, otherwise disable them, and the Darkness will abandon them in a black, visible wisp that lingers only for some seconds before dissipating.
TECH SPECS FOR INDIVIDUAL;
--STRENGTH; Below Average
--LONG-RANGE; Varies; most often None
--ENDURANCE; Below Average
--FLIGHT; None - even aerial units in 'life' show no ability to make use of their flight capabilities.
--SPEED; Varies. Shades are capable of attaining a run, though most simple shamble along unless they find prey.
--INTELLIGENCE; Poor
--OTHER; Remember - Shades attack in swarms. While individually only so much of a threat, when massed, said threat can grow exponentially.
ECHO;
A level above Shade, this requires a level of personal investment from the Darkness user. While still the result of a dead chassis becoming reanimated (or a living one taken unwillingly, or a handful of other options), the Darkness takes the 'imprint' of the Spark that once was in there, the result being a somewhat more intelligent undead. However, they are still only capable of simplistic instructions, and at this state they do feel pain - though a better description would be that they recognize damage to their bodies, and can accommodate for such to prevent further damage.
Nonetheless, with what intelligence they do have, they can be deadly. Though their tactics may be singleminded in combat, they have no fear. They fight to their fullest, without true regard for pain or mercy. They kill without a thought - they are incapable of such thoughts. In some cases, they are able to be bestowed with one of the most potent powers of the Darkness - the touch of death and decay.
Based off canon; IDW Devastation #6.
TECH SPECS FOR INDIVIDUAL;
--STRENGTH; Above Average
--LONG-RANGE; Varies
--ENDURANCE; Average
--FLIGHT; Based on original form; aerial-moded Echos can attain flight.
--SPEED; Above Average
--INTELLIGENCE; Below Average
--OTHER; Echos are capable of being instilled with the following Darkness-related powers; regeneration, death/decay touch.
CARRIER;
A living spark is infected with the Darkness - willingly. Full sentience is maintained, full intelligence is maintained, full capability is maintained - the only thing changed is that they are slowly, inextricably dying a little more every day. Bit by bit, they move towards 'Host' status, and will inevitably become a true Host unless the Darkness is somehow removed from them. This requires either a Herald - the only one capable of creating Carriers in the first place, aside from action by the Darkness itself - or an outside force able to remove the corruption of the Darkness.
Because of their new ties to the Darkness, Carriers find themselves with little need for Energon. They can still consume it at this state, but it is not required to power them. However, they find themselves wishing for a different kind of sustenance...and if they start using any of the powers possessed only by those devoted to the Darkness (decaying touch, dark energy blasts, ect), they will crave it.
TECH SPECS FOR INDIVIDUAL;
--All specs vary, depending on original form. One can assume there is a slight boost to all features, if anything.
--OTHER; Carriers, again, can be purged of this infection and return to true 'living' status. However, if they use any of the Darkness powers they have access to - regeneration, death/decay touch, energy bursts, then they will slide further and further towards the point of no return.
Please note that all such powers require at least a subconscious acceptance. If a Carrier fully resists the Darkness's urging to let it heal their wounds - then the Darkness will not.
HOST;
On the very cusp of life and death, Hosts are sentient forces of the Darkness - its soldiers, its generals. Their sparks are fully devoted (or at least accepting) to the Darkness, with no hope for salvation. As such, they are fully capable of accessing its powers. (See;
Darkness Writeup for canon notes). In Axiom Nexus, Hosts 'feed' off the living by using the Darkness to take their life energy (read; spark), and may also replenish their power levels by doing the same.
Hosts are capable of creating Shades and Echos, but not Carriers.
Based off canon; entire Dead Universe saga.
TECH SPECS FOR INDIVIDUAL;
--All specs vary, depending on original form. One can assume there is a slight boost to all features, if anything.
--OTHER; Hosts cannot consume energon; the related systems to processing such are no longer in use, and offer pain to them if they try. Hosts are also able to use all canon Darkness powers; regeneration/recovery from 'mortal' wounds, death/decay touch, energy bursts (some with debilitating effects to the victim), & spreading Darkness infection.
HERALD;
The primary Host of the Darkness. Shares many of the traits with standard Hosts, but possesses mastery over the Darkness and all its power. Can bend it to their will, and as such, bend other Darkness-affected mechs to their will as well - though results vary with how much sentience/power/will the other has.
Heralds can create all other levels of Darkness-infected mechs.
Based off canon; entire Dead Universe saga.
TECH SPECS FOR INDIVIDUAL;
--All specs vary, depending on original form. One can assume there is a slight boost to all features, if anything.
--OTHER; Heralds cannot consume energon; the related systems to processing such are no longer in use, and offer pain to them if they try. Heralds are also able to use all canon Darkness powers; regeneration/recovery from 'mortal' wounds, death/decay touch, energy bursts (some with debilitating effects to the victim), & spreading Darkness infection. As the primary host to the Darkness, their powers are the most potent of any other Darkness-possessed mech.