A regent will be automatically appointed if a ruler is:
incapable,
imprisoned,
under the age of 16,
away on a major journey: pilgrimage, hajj, or kow tow,
.
During a regency, the regent will take care of most matters of state, using their skills instead of yours, but considerably limiting your powers. During a regency, law changes are not allowed, and claimants with weak claims on your titles can push them. A ruler cannot take negative actions against their regent, such as revoking their titles or firing them from the council.
Selection of regent
If no regent is designated beforehand, a regent is selected automatically. It seems to be common for the chancellor, spymaster, or queen mother to be appointed as regent.
You can designate a regent by giving the relevant honorary title; this gives a +10 opinion bonus. The designated regent will become the regent should you need one, but may still be replaced through events. The honorary title of "designated regent" can be revoked, but once they become regent, the minor title of "regent" cannot be revoked.
Diplomatic actions during regency
During a regency, diplomatic actions require your regent's permission. They are more likely to approve kind actions toward characters they like and hostile actions toward characters they dislike. Their traits also affect which actions they will approve: for example, 
regents are reluctant to approve sending gifts. Whether a regent allows a marriage proposal can depend on whether you use the interaction menu of the groom/bride or the menu of their liege.
With the 
Conclave DLC, regents instead participate in council votes. During a regency, the council is empowered to vote as if all council laws are in their favor, and the liege cannot overrule the council.
Regency events
Regents may:
- face competition for control over the regency
- embezzle money from the ruler
- donate to charity on behalf of the ruler (ruler loses wealth but gains piety)
- steal demesne holdings from the ruler, if the ruler has at least 5
- lower crown authority or tribal organization
- attempt to kill the underage ruler
- attempt to declare the underage ruler insane, imprison the ruler, and eventually steal the throne
Competition for control of regency
If the regency is caused by the ruler being young or incapable, other characters may attempt to take over the position of regent:
- Men who are at court (your courtiers and councilors) and not leading troops: more likely if
, 
, or 
- Women only if they are queen or queen mother: more likely if or
Lowering of crown authority or tribal organization
One of the most frustrating things a regent can do is lower your realm's crown authority (or tribal organization). This can happen in two ways:
- A faction demands lowered crown authority or tribal organization. During a regency, this demand always succeeds. It is crucial to keep the faction from growing strong so your vassals do not present such an ultimatum during a regency.
- The regent decides to lower crown authority. This can only happen once to each liege, and does not apply to tribal organization. The regent must be landed and have their primary title within the relevant kingdom or empire. Mean time to happen is 120 months, modified by the following:
| Less likely | More likely | |||
|---|---|---|---|---|
 Content |
never |  Ambitious |
0.25 | |
 Charitable |
2.0 |  Greedy |
0.25 | |
 Just |
3.0 |  Arbitrary |
0.5 | |
Favors from underaged rulers (With Conclave)
Underaged rulers may receive an event whereby they felt intimidated by a councilor, and decided to owe said councilor a favor. This event can occur multiple times, but not more than once per councilor.
Strategies
Designate a regent who:
- Has high martial and stewardship, so your heir can use demesne levies to avoid or win faction wars. This is especially important with the Conclave DLC active, as you may find distributing excess titles difficult due to the council having a say.
- Is not a council member. (Their skills don't count twice in the calculation of state attributes, and council votes may be missing.)
- Likes your heir (Regents for incapable or imprisoned rulers should ideally be the heir)
- Is not landed in your de jure kingdom/empire, or is
, so they don't attempt to lower crown authority (without Conclave) - Is not landed, or is
, so they don't steal your counties - Is
or , so they don't embezzle money
For underage rulers, get your regent to like you. Award gifts and honorary titles. Choose a guardian for yourself who has high diplomacy skill: the "personal diplomacy" opinion toward children is evaluated based on a parent or guardian. You want their opinion to at least be positive, so they do not attempt to murder you or have you declared insane. A highly positive opinion is best, because regents have increased plot power, decide what actions you can take and (with Conclave) votes on the ruler's behalf.
Avoid having landed regents. Appoint invited courtiers, rather than landed vassals, to the positions of chancellor or spymaster. Landed regents may scheme to lower crown authority, independent of factions and regardless of opinion. If you do have a landed regent who is not , transfer them under a higher-rank vassal. If you can't do that, give them a higher-rank title that is outside of your de jure territory, so their primary title is not a de jure vassal of your crown law title. This is less of a concern with the Conclave DLC active, as crown authority is broken up into its component laws.
Dismiss a bad regent indirectly. Only a direct vassal or courtier can be a regent. Unmarried courtiers can be removed by marrying them out of your court (for men, using a matrilineal marriage). Regents can also be removed by granting them titles and then either granting independence or transferring vassalage to a higher-ranked vassal.
Consider making your adult heir the designated regent. They will gain prestige and are free to designate a new regent upon ascension.
Reduce the risk of entering a long regency:
- Avoid commanding troops during wars, as you may die or become
due to combat. One exception to this advice is when your capital is besieged, especially if you have claims on your enemy's titles (unwilling to set you free if you're imprisoned). - With
The Reaper's Due, severe illnesses may make you Incapable (bedridden). Consider getting a Court Physician with high Learning and high opinion of you. - Avoid playing as female characters as a Troubled Pregnancy can trigger a regency; the Final Months of a pregnancy will always trigger a regency for female rulers. Female characters can also die during childbirth.
- With
Way of Life, keep tabs on any vassal who dislikes you (or is a rival) AND has the Intrigue focus; you may be abducted (and imprisoned) by them. - Consider a succession law that prefers adult heirs: Seniority, Tanistry, or Feudal Elective
Remember that you'll need more votes in order to carry out actions during a regency: counts to kings require 4, while emperors require 5 (up from 3). The issue is further complicated if your regent is also a councilor: they will register one vote but the other will be treated as a "no", as if the seat were empty. (Bug?)