NationStates

The Vice-President will serve as acting President.

Supreme State Command take over until the Emperor is able to lead again. The Supreme State Command consists of Head of Government, Deputy Head of Government, Party Leader, Deputy Party Leader, Military Marshal, Deputy Military Marshal while the Legislative Chambers serve as advisors to the SSC.

If the president (currently Jxsn) is unable to lead somehow (despite FT-FanT tech), then Vice President (currently Alex) will lead until the president can lead again.
If neither can lead then there’s a whole (somewhat medium-small) chain/order, that I’m probably not gonna go into detail here unless this gets edited.

If the Bishop is unable to lead the diocese, the vicar general will either get the necessary permissions from the bishop (for example, if the bishop is ill but able to sign a document to that effect) or from the Holy See in Rome (if the bishop himself is unable to grant permission). However, during very short periods in which the bishop is unable to exercise his rights, the vicar general can still use the ordinary powers that come with the office of vicar general, which is enough for the usual, day-to-day tasks.

Parliament, both the Federal Council and House of Deputies, appoints a regent for the Emperor.

If the Chancellor isn't, that means a vote of no confidence had removed them, and the House of Deputies elects a new chancellor to form government, if not then a new election will be held.

Mr. Synne, the official "Leader" of Synne Industries acts more as a figurehead of the nation than a leader. If Mr. Synne is unable to make decisions the current head of the Greycoat Parliament will act as a temporary replacement.

If many members of the Greycoat Parliament are unable to serve for an extended period of time or are unable to make important decisions "doppelganger" AI will take over until the members are able to return.

In case the General Secretary cannot lead the Cosmician Commune, the head of the Parliament becomes General Secretary, or if that cannot lead or doesn't exist, a temporary council is formed and the head of that becomes temporary General Secretary.

No one knows it all anyway...

If my emperor can't rule，Then the Emperor Party will take over most of the empire's rule.

If the Emperor is currently unable to lead, then the Shadow Emperor takes the Emperor's place until either the Emperor is fit to lead again, or a new Emperor is found (depends on circumstances)

Due to the clusterfuck that is my government, there are 3 leaders that could suffer that fate.

Empereur Denis 1er of Charanêt-Boisgefelon: The Prince Impérial takes power as Régent de l'Empire until the Empereur retakes his throne.

Prince-Président Antoine Durocher: The Vice-Président is sworn in as Prince-Président Intérim.

Premier Ministre Adyle Monroe: Snap-Elections are called to appoint his interim, who bears the title of Second Ministre.

Normally the heir would act as a regent, but considering all children of the Queen are legal minors as of 1968, the privy council would act as a temporary regency council with the closest family member of the Queen as nominal regent.

Decisions are made by the departments under which their jurisdiction fall, with one exception: War may not be declared.

If Corvisia’s symbolic leaders, The Ravenlords, should be unable to lead, their mantle of Ravenlord is held until they can recover or a suitable replacement is elected and undergoes the rite of reckoning.

The mantle of Ravenlord is largely symbolic, and the duties of the Ravenlord are mostly ceremonial or military in nature, with little actual granted political power, more than just the prestige of the title.

The mantle of Ravenlord is bestowed upon one who is deemed a hero of the revolution, or a savior of Corvisia, and while the rite is intense and dangerous, it is not too long, and while the news of a Ravenlord stepping down or being appointed is national news, the country can continue to operate in its full capacity.

The vice-president will take over the president's role for as long as necessary.

When the president is unable to serve, such as in the case of illness, the vice president takes over.

The 1st in line for the throne (in this case the emperor's wife) takes over as Emperor/Empress until the other is fit to lead again.

The Deep Council of Ecological Fascism would rule collectively.

If that happens, the Vice-president do the president's job in that time.
If no one can lead, the power will be handed to the Queen and Parliament

Should the Lord Great Protector be unable to discharge his or her duties as head of state and of government, then the President of the Humane Senate, Chief Justiciar, and Steward of the Government shall jointly lead the nation until the Lord Great Protector is once again able.

Should the Prime Minister of Drongonia be unable to lead, the deputy Prime Minister becomes the Acting Prime Minister.

If the Prime Minister is unable to lead for more than 90 days and it is uncertain whether they will return to duty, the Deputy Prime Minister will be sworn in as Prime Minister.

Under the Regency Act promulgated by the Prince last August 2019, the Prince's mother will discharge the powers of the Prince until the temporary incapacity has been terminated. There is no provision for the discharge of the duties of the Chief Minister, however, it is believed that the most senior cabinet minister will temporarily preside.

The 12 year old vice dictator leads the nation.

All non-emergency government activity ceases, while emergency government activities are handled by the cabinet headed by the vice-president

Big shock here but the king actually gives full authority to his wife. If she cant lead then it goes to the advisor.....if they cant lead then the eldest son leads. then if he cant lead it goes to his wife. Can you see a pattern?