What does the Formidable Banneret trait do in CK3?

Formidable Banneret: Prowess +3. Patch 1.20.0.3, from game/common/traits/00_traits.txt.

What is the trait ID of Formidable Banneret?

education_martial_prowess_3 — console: add_trait education_martial_prowess_3, remove_trait education_martial_prowess_3.

Education trait

Formidable Banneret

add_trait education_martial_prowess_3remove_trait education_martial_prowess_3

Trait ID education_martial_prowess_3. Console commands work with the debug mode on (launch option -debug_mode, then the ` key) and act on the character you play.

Formidable Banneret (trait ID education_martial_prowess_3) is an education trait in Crusader Kings III: Prowess +3. Some cultures and faiths add more (1 bonus on the page). Patch 1.20.0.3, from game/common/traits/00_traits.txt.

Quick answers (2)

What does the Formidable Banneret trait do in CK3?: Formidable Banneret: Prowess +3. Patch 1.20.0.3, from game/common/traits/00_traits.txt.
What is the trait ID of Formidable Banneret?: education_martial_prowess_3 — console: add_trait education_martial_prowess_3, remove_trait education_martial_prowess_3.

The Formidable Banneret led troops and fought bandits even before their majority, battle-hardened into a determined combatant.

Effects

Prowess+3

Bonuses from culture and faith

Extra effects this trait gives only when the character's culture or faith has one of these.

Culture with Futuwaa, Druzhina, Garuda Warriors, Chanson de Geste or Martial Admiration

Same Culture Opinion+3
Prestige+0.3/month

Source: game/common/traits/00_traits.txt and the English localisation, Crusader Kings III 1.20.0.3.