What makes a good Eparch in CK3?

Stewardship Skill Stewardship (max 50), Diplomacy Skill Diplomacy (max 50), Diplomat +10, Overseer +10, Administrator +10, Schemer +10, Erudite +10, Diligent +5, Just +5, Stubborn +5, Fickle -5, Impatient -5, Education Republican Knowledge 4 Trait +8, Education Republican Knowledge 3 Trait +6, Education Republican Knowledge 2 Trait +4, Education Republican Knowledge 1 Trait +2, Belongs to a Powerful Family +8, Belongs to a Dominant Family +12, Governor Trait +4, Capital Bureau 02 Building line 0 and The Capital has Panem Et Circenses County Modifier +5 (the game's aptitude breakdown, patch 1.20.0.3).

What tasks can the Eparch do?

Appease Populace, Support Troops, Enforce Public Order and Develop Capital.

Administrative court

Eparch

Eparch is a court position in Crusader Kings III; its aptitude rests on Stewardship. Aptitude also comes from Diplomat (+10), Overseer (+10) and Administrator (+10). Base salary 0.5 a month; revoking it costs 200 prestige. Patch 1.20.0.3, from game/common/court_positions/types/00_admin_court_position.txt.

Quick answers (2)

What makes a good Eparch in CK3?: Stewardship Skill Stewardship (max 50), Diplomacy Skill Diplomacy (max 50), Diplomat +10, Overseer +10, Administrator +10, Schemer +10, Erudite +10, Diligent +5, Just +5, Stubborn +5, Fickle -5, Impatient -5, Education Republican Knowledge 4 Trait +8, Education Republican Knowledge 3 Trait +6, Education Republican Knowledge 2 Trait +4, Education Republican Knowledge 1 Trait +2, Belongs to a Powerful Family +8, Belongs to a Dominant Family +12, Governor Trait +4, Capital Bureau 02 Building line 0 and The Capital has Panem Et Circenses County Modifier +5 (the game's aptitude breakdown, patch 1.20.0.3).
What tasks can the Eparch do?: Appease Populace, Support Troops, Enforce Public Order and Develop Capital.

The Eparch is the main administrator and ultimate authority of the capital, second only to the reigning monarch.

• The Eparch Court Position will oversee the capital's administration

What makes a good Eparch

The game's own aptitude breakdown for this position — every part it adds up:

Part	Aptitude
Stewardship Skill	Stewardship (max 50)
Diplomacy Skill	Diplomacy (max 50)
Diplomat	+10
Overseer	+10
Administrator	+10
Schemer	+10
Erudite	+10
Diligent	+5
Just	+5
Stubborn	+5
Fickle	-5
Impatient	-5
Education Republican Knowledge 4 Trait	+8
Education Republican Knowledge 3 Trait	+6
Education Republican Knowledge 2 Trait	+4
Education Republican Knowledge 1 Trait	+2
Belongs to a Powerful Family	+8
Belongs to a Dominant Family	+12
Governor Trait	+4
Capital Bureau 02 Building line	0
The Capital has Panem Et Circenses County Modifier	+5

The holder gets

Prestige+1/month
Monthly Influence+25%

Tasks

Appease Populace
The Eparch Court Position will attend to the needs of the citizens of the capital.
Support Troops
The Eparch Court Position will oversee the organization of the local garrisons and ensure an effective command.
Enforce Public Order
The Eparch Court Position will have soldiers patrol the streets to keep the peace and secure public order no matter the cost.
Develop Capital
The Eparch Court Position will put the city's administrators to good use to develop and improve the city.

Who may hire it (valid_position) (1 line of game script)

highest_held_title_tier >= tier_empire

As written in game/common/court_positions/types/00_admin_court_position.txt.

Who may hold it (valid_character) (5 lines of game script)

scope:employee = {
	eparch_validity_trigger = {
		EMPLOYER = scope:liege
	}
}

As written in game/common/court_positions/types/00_admin_court_position.txt.

Shown when (is_shown) (2 lines of game script)

government_has_flag = government_is_administrative
is_independent_ruler = yes

As written in game/common/court_positions/types/00_admin_court_position.txt.

Source: game/common/court_positions/types/00_admin_court_position.txt, common/court_positions/tasks, common/script_values and the English localisation, Crusader Kings III 1.20.0.3. Salary is the base before the realm-size and cultural-era multipliers.