How can a dynasty of immortals be overthrown?

Question

On a planet not too different from Earth, in a land quite similar technologically to ancient Rome, there is a dynasty of absolute monarchs that have remained in power for centuries. They enjoyed periods of prosperity, peace, and popularity, but within the past fifty years or so, discontent has arisen as the public believes that the monarchs have been abusing their power and doing only what they want to do.

In desperation, King Shenaeth the Magnificent goes to the temple of his ancestors, where he prays for help. To his surprise, a potion appears before him, along with the murmur of words through the air, telling him that if he drinks the potion, he and his descendants will be immortal (they have the same type of immortality as the folks described in How would a war between immortals be fought?; they can regenerate lost body parts as well as avoid the typical non-violent causes of death.).

Shenaeth drinks the potion, and announces to the people the next day what has happened. They now cannot kill him! He reminds them that he has total control over the military, too - did I mention that the soldiers already worship him as a god, and devote their lives to him? - and sends an implicit message: He is supreme and immortal.

Over time, Shenaeth's kin multiply. He remains at the head of the country for several centuries, during which he builds up an army (of immortals) and conquers much of the globe. Eventually, any virtues he may once have had disappear, and he begins exploiting the population. Discontent rises, and several groups of underground fighters (with overwhelming public support) decide to plan a revolution to overthrow the government.

How can these fighters overthrow the government of immortals? They don't need to kill Shenaeth; they simply need to remove him and his family (and extended family) from legal, military and political control over all the lands.

Additional specifics:

• The standing army is roughly 7.5 million troops, with all but 10,000 being mortal. However, almost all of the top officers (~95%) are immortal, and have great sway over their troops.
• The population under Shenaeth's control is about 200 million people. Rebel groups consist of about 5 million troops (in a standing army), while estimates put folks "in reserve" (those who would fight for the rebels if need be) at around 25 million. The rebel forces are (extremely) loosely organized, and there is no central command structure.
• The overthrow should last for at least 25 years - enough for a government to get control over the region and start implementing pro-democracy policies.

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I've considered the idea that power rests in the hands of the people, and that the people could simply choose to recognize a new (rebel-led) government as legitimate, but they would still eventually be overpowered by Shenaeth's military.

Answer 1

Bring the house down on them. Literally.

This is a long-term plan, but should have a chance to succeed.

1. Scale down or cease all open hostilities to promote complacency.
2. Recruit a famous architect sympathetic to your course.
3. Have it come to the king's attention that someone else (abroad) is planning to have a great monumental palace built.
4. Wait for his desire to grow, then have the architect approach the king with a grandiose design for a giant hall.
5. Entice the king to order the construction and build the hall at mostly his expense, include cleverly hidden stress points. This will take some years.
6. Infiltrate dedicated rebels among the servants as sleepers.
7. When the time for the grand opening nears, subtly spread rumors about how various kin are planning great tributes to gain the king's favor. Encourage everyone's ambitions to ensure as many of the immortals as possible attend the opening ceremony.
8. Shortly before the opening contact and instruct the sleepers on how to find and collapse their assigned stress points.
9. Send volunteers dressed as priests to the ceremony. Let them loudly proclaim the Gods' wrath. Do this where the soldiers, guards and public can hear.
10. Give the signal and collapse the hall, imprisoning most of the immortals under tons of stone.
11. Have your gathered mob take up the slogan that the Gods want all immortals buried in stone. Overwhelm the remainder with nets and bury them under as much stone as you can.
12. Hopefully, the mortal soldiers will be so shocked and demoralized that you can avoid a civil war, otherwise things will still get bloody.
13. For bonus points, fill up the ruins with earth and build a monument to the folly of the immortals on top of it.

Pros:

• Plays on the vanity of the immortals, probably their biggest weakness
• The army would most likely not be inside the city for the ceremony.
• It can be over before anyone has time to realize what's going on.
• The irony of having the king finance his own fall makes for a great story.

Cons:

• There will be a lot of suffering during the years of the plot, plus the risk of early discovery.
• Volunteers may lose their nerves and fail to collapse their points (which they probably realize means their own death)
• If the rebels fail to hold the ruins, the loyalists can just dig out the immortals again, and boy will they be pissed.
• Finally, this will leave a horde of maddened immortals buried in the ground, to be unleashed by some future archaeologist.

Answer 2

I see two possible avenues.

1. It would have to be a military coup. So start with the generals that are not immortals themselves. Convince them that their life would be better under new management and to use their soldiers to take over. If enough of the military changes allegiance their power will be broken, at least over large swathes.

2. Work discontent into the Kings younger family members who are constantly under his command and knowing that he will live 'forever', never giving them a chance to be out of his shadow. They can start a civil war and they might know how to kill each other, such as staking someone with chains to a large pyre and burning them to ash.

Once an effective way to kill them is understood, overthrow of the whole family would be much easier, pushing them back into the shadows to slowly gather power again.

Answer 3

Following the "rules for rulers" logic proposed here, it would not take long before the offspring started fighting for power.

Overthrowing the dynasty would be hard in a sense that the immortals will always be there, but they would have very little power as every immortal converges to the king's morality while jostling for a more or equally powerful empire.

TLDR of post and video: The transition from a single immortal god-emperor to multiple god-like immortal entities would at one point topple the scales of power, resulting in a balance of smaller and smaller nation-states until everyone was immortal. At which point we can all stop fighting because it'd be pointless anyway.

Answer 4

The immortals are not omnipotent. Other than being unable to die, they are no different to anyone else.

Kidnap and disposal by rebels would be the best method. They kill them (even though they wont stay dead) and get rid of the bodies.

Rebels could infiltrate the military and capture the immortals through stealth (poison would work well). Once captured, they seal the immortal in a barrel full of concrete and drop it into the deep ocean.

The immortal won't die but you are not going to see that immortal again for a very very long time.

There would also be a good chance the immortals would be doing exactly the same thing to each other to rise up the ranks.