Kheldian
Kheldians are an alien race from outside the Milky Way galaxy in the world of the City of Heroes MMO.
Kheldians are energy-based beings with a short (10 Earth-year) lifespan. Their lives are extended, though, through the symbiotic merging with a coporeal being. The merging offers benefits for both parties as the union results in a far more powerful being with a much longer lifespan.
Kheldians also can transform into one of two "legacy forms". One form is a squid-like "nova" form which is adept at flight and has access to considerable energy-based powers. The other is a lobster-like "dwarf" form, which has far greater strength and endurance than normal. It is believed that these forms were the first beings that merged with Kheldians, which is why transforming into these states is considered second nature for all Kheldians. These are also the only physical states that a "pure" (unmerged) Kheldian can take in order to communicate with corporeal beings, although it does drain their energy to inhabit these forms for any length of time.
At some point in their past, a civil war broke out amongst Kheldians as to how to further extend their lives. A segment decided they would use their abilities to suck the life forces out of others. The others decided to extend a friendlier hand toward the universe. This schizm would continue for centuries and transform the Kheldians into two separate species.
It is unknown if "pure" Kheldians still retain any kind of gender since they have evolved into energy beings.
Kheldian Divisions
Peacebringers
(See also the Paragon Wiki entry.)
Peacebringers represent the mainstream Kheldian species. They are considered "pure" Kheldians. When they first appear as a merged being, they possess limited energy abilities and an inherent flight power, but they also gain more abilities depending on those they team with. In addition to the power they gain through merging, they can also revert to their Kheldian "legacy forms" to further augment their abilities.
All Peacebringers are considered "natural" in origin.
Peacebringer Redeemer
By rule, Peacebringers must only merge with a willing host. But on rare occasions, a Kheldian may be required to merge with a host that is dead. One such example was Horus, even though the merging was done when he was recently deceased. It is unknown just how a Kheldian knows whom to inhabit, as speculations often point to a "higher authority".
These Redeemer Peacebringers are considered troubled beings, since the merging is often done to pursue a need for justice. These can often result in an obsession that, once completed, will leave the joined being searching for a new cause, or for any kind of purpose in life. This often leads such a Peacebringer to take unneeded risks, or to even be suicidal.
Daybright of the Guardians of the Dawn is the most recent Peacebringer Redeemer.
Awakened Division
After the debut of a Kheldian warrior with a Paragon Policeman to produce Sunstorm, one of the first career paths for the merged Kheldians was with the Paragon City Police Department and their new Awakened Divison. This has allowed Peacebringers to not only bolster the department's ranks, but to also keep a watchful eye on their fellow Kheldians, as well as to deal directly with the threat of the Nictus.
One such Awakened Division officer is a Peacebringer named Dreadlaw who also serves as a special enforcer for the Kheldian home world.
Nictus
(See also the Paragon Wiki entry.)
The breakaway segment of the Kheldians are known as the Nictus. One of more notorious of merged Nictus is Requiem.
Nictus sustain themselves by absorbing the life-essences of living beings, including energy-based beings such as other Kheldians. Although initially considered an act of desperation, the Nictus now believe this is their greatest power. They abhor merging with "lesser beings", although they understand the need and the benefits of such a symbiotic union.
Nictus are science-based, since their abilities to drain the lives of others come through centuries of experimentation. They see their fellow Kheldians as not rivals or enemies... but as eventual food.
Warshades
(See also the Paragon Wiki entry.)
Within the ranks of the Nictus are those who have returned back to the fold of their Kheldian brethren.
Warshades are not just "darker" versions of peacebringers. They retain their Nictus ability to "feed" off the life forces of others, although they have to work hard to refrain from using it, and to avoid using other Nictus devices such as Shadow Cysts. They are stronger in defense than Peacebringers, as well as utilize an inherent teleport power instead of flight.
Like their Nictus brethren, their origins are Science-based.
Warshade Redeemers?
It is unknown if there ever was a Warshade that ever became (or tried to become) a Redeemer. Most have adhered to the Kheldian Lifebond which also specifically prohibits merging with the bodies of dead hosts.
See Also
Other References
The Kheldians first appeared in the Blue King Comic incarnation of the City of Heroes comic series as the species that saved a mortally-wounded Horus during the Rikti War.
The Kheldian Talmyia appeared in an alternate future in Issue #10 of the Guardians of the Dawn Spotlight series, demonstrating its ability to use the Bright Nova form even without merging with a human host so it could converse with Doc Tor. But it also mentions that it cannot stay in that form for very long without either merging with a host or reverting back to its energy form.
(See the Paragon Wiki entry for more information.)