Companions

Introduction
Companions are playable and recruitable characters throughout the game, some will join you quite easily with exchange of a few words while others may require you to fulfill your promise of helping them pursue their goals before they come to the decision of longtime stay. All companions have alignments, unique personalities and perspectives which make them either support or despise your decisions, party reputations, or even come to blows with other members, forcing the player to choose sides. The main character can also develop romance relationships with certain companions.

You may have up to six characters in your party, main character included. In Enhanced Editions of the game, you may also choose to play with a fully customized party like in the Icewind Dale series, with the first character you created being your main character. Companions come with various classes and abilities, it’s up to players how to make their own ideal parties.

In original versions of the games, companions who are under-leveled at the time of joining will have their levels automatically adjusted based on average party level, In Enhanced Editions however, they’re given a certain amount of experience points (XP) for you to manually level them up to gain more control of their status. The highest XP they can have at the time of joining is: 32,000, 250,000, 1,250,000(SoA), and 2,500,000(ToB). Each time the party gain XP, the game will try to divide them evenly among characters, undividable points are then distributed according to positions of the character portraits from “top” to “bottom”, main character has the tendency to gain more XP than other party members. There’re also cases in which each character gains an equal amount of XP  individually. None of the companion status from Baldur's Gate carries over into Baldur's Gate II.

Interactions
There are ways to break up pairs:

Romance in Siege of Dragonspear will not  carry into Shadows of Amn.
 * 1) Send one into a area the party is not planning on returning to, then kick them from the group
 * 2) Have the one you're not planning to keep killed

Romance will continue in Throne of Bhaal if you  have completed the romance part in Shadows of Amn and start  Throne of Bhaal by importing the savefile or continue from Shadows of Amn straight into the expansion pack with the same party.

Most companion conflicts apply only in Shadows of Amn.

Players may use NPCs as mules to store items on, but this should not be considered 100% reliable, sometimes their dialogues will also be reset or moved to unpredictable stages even with precautions such as adding them to the party occasionally.

Useful links

 * Walkthroughs of Baldur's Gate and Baldur's Gate II by Dan Simpson