|“|| One Awake! Two Asleep!
As specifically explained in the Underworld novelization, the Chain served three functions: first, as an ingenious power-sharing arrangement among the three Elders, avoiding conflict among them by ensuring that only one of them was in command in any given century; and second, to provide each Elder with a much-needed respite from the demands of eternity; and the third was to keep Marcus from ever getting the chance to free his twin brother.
What the term itself actually represents is unclear, although it is commonly assumed to mean the chronological order in which the Elders rule. Alternatively, it refers to the chain of memories transmitted from Elder to Elder, one memory for three, thus, Selene would be breaking the Chain by awaking an Elder herself more than by awaking him at the wrong time.
The Chain follows a neverending rotary cycle which involves the three Elders taking turns in ruling over the Vampire Coven and their former Lycan slaves. By the end of the 14th Century, it is seen to be established that while one rules the other two slumber in coffin-shaped tubes hidden within the various headquarters of the coven. According to the novelization of Underworld, while in hibernation, an Elder is hooked-up to life-support, a intravenous feeding system, designed to sustain an Elder during their two-century hibernation; and according to the novelization of Underworld: Evolution, a Vampire Elder enters hibernation via fasting.
After being awoken from hibernation, the elder is in an incredibly weakened state, having being deprived of blood for an extended period of time. In modern times, this is compensated for by attaching multiple tubes to the elder's body and pumping large amounts of blood directly into the elder's system, allowing their frail bodies to regenerate from the effects of hibernation, which causes their bodies to enter a mummified state.
It is possible that the reigning elder remains in power until the newly-awakened vampire elder fully recovers from the effects of their hibernation, allowing the elder who had just awakened to focus completely on recovering without being burdened by politics, while also allowing the elder who would be leaving the throne time to conclude his/her affairs, make arrangements for the next time they are in power, and/or to prepare to enter hibernation.
The Elder currently reigning keeps the slumbering Elders under close watch and heavily guarded, transporting them to other locations if necessary. During Viktor's reign, the other Elders were kept in the depths of the mountain beneath the castle but moved by ship to different Coven households, as seen in Underworld: Rise of the Lycans.
Every century a different Elder is awakened with a small amount of blood from the currently reigning Elder, thus giving a detailed record of their reign, informing the awakening Elder of the times through blood memories.
At what point the Elders agreed upon the Chain is not known apart from Viktor's claim to Selene in Underworld that the Elders have rotated for fourteen consecutive centuries. After Underworld, the cycle of hibernations was generally assumed to follow this simple pattern:
- 600-700 A.D. - 1st reign of Viktor
- 700-800 A.D. - 1st reign of Amelia
- 800-900 A.D. - 1st reign of Marcus
- 900-1000 A.D. - 2nd reign of Viktor
- 1000-1100 A.D. - 2nd reign of Amelia
- 1100-1200 A.D. - 2nd reign of Marcus
- 1200-1300 A.D. - 3rd reign of Viktor
- 1300-1400 A.D. - 3rd reign of Amelia
- 1400-1500 A.D. - 3rd reign of Marcus
- 1500-1600 A.D. - 4th reign of Viktor
- 1600-1700 A.D. - 4th reign of Amelia
- 1700-1800 A.D. - 4th reign of Marcus
- 1800-1900 A.D. - 5th reign of Viktor
- 1900-2000 A.D. - 5th reign of Amelia
- 2000-2100 A.D. - Intended 5th reign of Marcus
However, if dialogue in later films (and dates given in the novelizations) is to be believed, this pattern is proven wrong. For example, Underworld: Evolution shows that all three Elders were awake at the same time in 1202 AD, witnessing William Corvinus being captured by the Death Dealers, the original Werewolf having just ravaged an entire village and turned several dead civilians. Marcus, who had been promised by Viktor that his brother would not be harmed, was betrayed by Viktor and Amelia to keep William and in turn Marcus himself under control. This may not be a retcon, as it is possible the waking Elder awoke the other two upon learning of William's location.
Given the numerous continuity errors in the Chain that are never explained, it is very likely that the Chain was initially supposed to have run uninterrupted for 14 centuries, but was retconned in later installments for unknown reasons. It is also possible the record of the Chain was altered by Viktor's efforts in hiding and rewriting Vampire history.
However, at what point the Elders agreed to hibernate when not reigning, whether at the Chain's inception or an added measure included centuries later, is also not known. If the latter, the hibernations may have been devised by Viktor and Amelia with the intention of keeping Marcus and William separate from each other forever.
The cycle would seem to have followed something similar to the following pattern:
- 1350-1410 A.D. - 1st sole reign of Viktor 
- 1410-1450 A.D. - 1st reign of Amelia (after 60 years in hibernation)
- 1450-1500 A.D. - 1st reign of Marcus (after 100 years in hibernation)
- 1500-1550 A.D. - 2nd reign of Viktor
- 1550-1600 A.D. - 2nd reign of Amelia
- 1600-1650 A.D. - 2nd reign of Marcus
- 1650-1700 A.D. - 3rd reign of Viktor
- 1700-1750 A.D. - 3rd reign of Amelia
- 1750-1800 A.D. - 3rd reign of Marcus
- 1800-1900 A.D. - 4th reign of Viktor
- 1900-2003 A.D. - 4th reign of Amelia (after 150 years in hibernation)
- 2003-2100 A.D. - Intended 4th reign of Marcus (after 200 years in hibernation)
At the very end of Amelia's reign, the Chain was disrupted by Selene, who awoke Viktor early to reveal the Vampire regent Kraven's treacherous alliance with Lucian. Amelia was then murdered by Lycans, and Viktor was killed by Selene via partial decapitation, completely ending the Chain with Marcus surviving, until his death too when he is sliced apart by the propeller blades of a crashed helicopter outside William's prison. If new Elders are chosen, the Chain may restart anew.
- It is interesting to note that the Chain occurs in the order of V-A-M, as those are the first three letters of the word Vampire, as well as being the first letters of the Elders' names consecutively.
- It is stated that Viktor used Lucian to convert humans into Lycans for 200 years, despite the hundred year cycle.
- The fan novel Blood Enemy- featuring an alternate beginning to the war before Underworld: Rise of the Lycans was released- includes a scene where Marcus awakens Viktor as part of the Chain, revealing that part of the awakening includes a ritualistic speech where Marcus reminds other vampires present of the advantages of the Chain compared to mortal methods of exchanging and sharing leadership. Once Viktor is awakened, Marcus retreats to a separate room to prepare for his own slumber while Viktor is revived through donated blood, with the rest of the Coven ordered not to interrupt either Elder unless the situation is particularly dire.
- ↑ "Enough! Have I not increased our holdings tenfold since Marcus and Amelia took their sleep?" ~Viktor
- ↑ "Nearly six centuries had passed since that night. Yet the ancient feud proved unwilling to follow Lucian to the grave." ~Selene
- ↑ "I've never underestimated Kraven's lust for advancement but Viktor believed him and that's all that matters." ~Kahn
- ↑ "This is his war. Viktor's. And he's spent the last six hundred years exterminating my species." ~Lucian
- ↑ "How many innocents have you slain in your six-century quest to avenge your family?" ~Alexander Corvinus
- ↑ "He was exiled over three hundred years ago." ~Selene
- ↑ "Tanis has been hiding here since Viktor's order." ~Selene off Andreas Tanis
- ↑ "You've been awakened a full century ahead of schedule." ~Kraven
- ↑ "It is Marcus' turn to reign, not mine!" ~Viktor