Game concept

Best Friend

The game also links it as Best Friends, Best Friend's, Best Friends'.

From the game's encyclopedia

A Best Friend is a Special Relation indicating lifelong dedication and support. It is a stronger Special Relation than a Friend. A Character can only have one Best Friend.

The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.

Best Friend is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Best Friend is a Special Relation indicating lifelong dedication and support." It is part of Special Relation. The game also links it as Best Friends, Best Friend's and Best Friends'. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.

for a guide, post or blog

Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.