The Shadow Clan are a group of creatures who live in SlugTerra. They are territorial and aggressively defend their Territory by throwing Slugs. Members of the Clan are rarely seen alone, tending to travel in groups and attack en masse. No one knows where the Shadow Clan came from, just that they were the first creatures in SlugTerra. Although the Shadow Clan does not use blasters or Mecha Beasts and appear to have minimal infrastructure they have been shown to have advanced technology. The Shadow Clan is a sort of universal persona non grata, though this suits them just fine. In general they avoid the affairs of other species -- with the exception of Slugs -- and keep to themselves unless disturbed. While they can understand the common language of SlugTerra (I.E.: the language the show is dubbed in), they tend to ignore what outsiders say to them. When Eli asks what the Shadow Clan wants, their leader cryptically replied "We want the same thing that all Shanes want," but doesn't specify what exactly that is.
Supposedly, the Shadow Clan had high respect for the Shanes. But after Will Shane's "disappearance" they lost all respect for the Shanes. The Clan has a growing respect for Eli and, as of "Lightwell", the Shane Gang as a whole.
The Shadow Clan is led by a Shadow Clan member who appears to have a crown on his head, worn in the style of a helmet. This member of the Clan also seems to have battle armor equipped.
The Shadow Clan have a poor reputation in SlugTerra, with Pronto referring to them as "the most evil thing in all of SlugTerra and with even Dr. Blakk fearing them. Despite this, the Clan appears to be the protectors of SlugTerra, as seen in "What Lies Beneath".
In Season 1 the Shadow Clan appeared as large, bipedal, primate-like creatures. Their tails have adapted finger-like appendages for grasping Slugs and they can easily attack while on all fours, moving similarly to galloping. They have a series of pods located on their backs that are used to house Slugs.
Their height seems to vary amongst the Clan. While most are as tall as Cave Trolls, one member, the Clan leader seen in "Lightwell", was almost twice the height of Eli Shane.
- Slinging: The Shadow Clan are able to sling Slugs without the aid of a blaster. Their tails are prehensile and strong enough to stop a moving mecha-beast and its rider.
- Communication: The ability to understand the language that Slugs use. They are also able to re-direct a Slug's abilities over a larger area. So far, this has only been seen while a Slug is in its protoform. During this process the affected Slugs glow green. The Shadow Clan can also make all slugs in the area glow green. In "Shadows And Light" this ability allowed them to find the Fandangos the Shane Gang was moving through their territory, though that may have been an unintended consequence of syncing Slugs.
- Teleportation: They are capable of near-instantaneous movement and are able to chose their target destination with a high degree of accuracy, allowing them to avoid dangerous obstacles and initiate surprise attacks.
- Climbing: A gecko-like ability that allows the Clan to climb without needing to seek out handholds. They are also capable of moving while parallel to the ground on walls or while suspended from ceilings.
- Heat vision: Despite living in some of the darkest caverns in SlugTerra, the Clan does not seem to have particularly notable night vision. Instead they appear to be able to see heat signatures, as seen in the episode "Shadows And Light".
- Melee combat: Although this is not a skill often used in SlugTerra, Clan members were able to defeat several of Blakk's underlings without the need for slinging.
- Speed: Clan members are fast enough to keep up with running Mecha Beasts, including Vance Bolt's horse mecha when it isn't using its turbo boost mod.
- Shadow Walker: A device that allows for teleportation. It is currently unknown if a Clan member needs to be in possession of one of these devices in order to teleport -- seeing as Clan members in both "What Lies Beneath" and "The Return" were shown to be carrying them around -- or if it is an ability innate to their species. In "Lightwell", the leader of the Clan used his Shadow Walker to open a physical path to the Well. This may mean that the orb has multiple purposes or there may be additional features unique to the leader's version of the orb.
- Shadow Talker: A crown-like device which allows the wearer to converse with the Shadow Clan. When Eli uses the Shadow Talker to talk to the leader of the Shadow Clan, he is told that he is the only human to be able to tolerate the effects of the device and that not even his father could use it. So far, only one of these has been seen. Since Eli is the only one capable of using it, the Shadow Talker may be a unique device, much like the blaster Eli receives from Red Hook.
While early in the show the Shadow Clan was presented as a dangerous force that no one wanted to encounter, multiple weaknesses have been introduced as the show progresses.
- The energies of the Deep Caverns: While no member of the Clan has yet to be seen beyond the barrier to the Dark Banes territory, it is known that the Shadow Walker does not work there, allowing only for one-way teleportation into the cavern. It is unknown if all Shadow Clan technology, and possibly their innate abilities as well, do not work within the Deep Caverns or if this weakness is because of the existence of the portal barrier, purposely making Shadow Walkers useless to the Dark Bane as a means of escape.
- A Photomo's Dark Light ability: This appears to remove the Clan's ability to teleport and also either weakens or temporarily blinds them, given the manner in which they fled from it. They do not appear to have a similar weakness to the natural light within the caverns, since they were able to successfully attack Blakk's henchmen and kidnap Eli in a well-lit cavern. Unlike the High Plains Monster, the Clan does not have a notable weakness to fire, although they're are not impervious to it either. In "Inheritance", the presence of lava failed to deter the Clan and barely seemed to slow them down.
- The energy of the Lightwell is able to heal slugs, but close proximity to the Well limits the Clans' ability to teleport, making them unable to choose their exit location.
- Negashades: While unconfirmed in the show, Shadow Clan members are weak against this kind of Slug in Battle For Slugterra.
- As seen in "Shadows And Light", the Shadow Clan are able to produce a scream capable of stunning their foes.
- In "The New Kid Part 1" it is revealed that even Ghouls are afraid of them.
- In "Battle For Slugterra" they use Pyringos, contrary to the disapproval of Ghouls they display in the show.
- An image in a book seen in "Back to Blakk" appears to depict a Shadow Clan member attacking a fleeing Dark Bane, implying past conflicts between the two species and the possibility that the Shadow Clan were the ones to seal the Dark Bane in the Deep Caverns. In the narration of this scene, Blakk says that the records he found spoke of "good and evil", opening the possibility that the Shadow Clan were not always perceived as monsters.
- In "The Slug Run", Burpy shows fear when the Clan appears, even though he should be familiar with them due to Will Shane's meetings with them from years prior.