Jaheira

Jaheira is a Fighter/Druid who can be recruited in both games. With the ability to cast healing spells and stand up reasonably well in combat, she makes an excellent addition to any good or neutral party. The only downside is that her multi-class nature means that she is unlikely to reach a high level in either class, although this is less of an issue in BG2.

Baldur's Gate 1

Jaheira can be found with her husband Khalid at the Friendly Arm Inn. You must recruit them both at the same time, and if one leaves or is removed from the party, the other will also depart.

Siege of Dragonspear

If present, Jaheira will leave your party after the first chapter. You can recruit her again later.

Baldur's Gate 2

Jaheira can be found near your cell at the beginning of the game. Khalid does not appear in BG2 so there is no requirement to recruit him in order to keep Jaheira in your party.

Jaheira has a fairly long side-quest in BG2 which is not dependent on whether you are in a romance with her (although this will affect a few of the dialogue options). You must continue with the quest in order to keep her in the party, although it is possible to finish the game without completing it.

Romance

If your character is male and elven, half-elven or human, he can enter into a romance with Jaheira.

The key to romancing Jaheira is to listen every time she asks you something and not push things too fast (the reason for this will be obvious before you finish the first chapter of the game). Reassure her that she has taken the right path by choosing you over her initial feelings as druid, particularly when it comes to maintaining balance.