Imoen

Imoen is a Neutral Good human thief and the first NPC available to become a party member in Baldur's Gate and Baldur's Gate II: Shadows of Amn. She is the childhood friend of Gorion's Ward. They both grew up together in the library fortress of Candlekeep from the time she was brought there, when they were both about the age of 10. "He-ya! It's me, Imoen!"

Baldur's Gate
In the Prologue she will greet you when you approach the front of the Candlekeep Library proper. She surprises you by knowing more about your impending journey with Gorion than you do. At the start of Chapter 1, she will hail you immediately after the night's events just outside of Candlekeep, and join your party despite any answer given in dialogue.

Imoen is a pure Thief, and has the best overall stats of any companion in the entire saga. Being a thief, she is a valuable companion, as the particular skills a thief has can be very beneficial; detect/disarm traps, open locks, pick-pocket, etc. She also has a very high Charisma, making her an effective leader in regards to the party's appearance, likely yielding better prices in shops and good reactions during particular conversations. She has in her inventory at the start: At level 1 she has 8 hp and Weapon Proficiencies in Small Sword and Bow ("classic" Baldur's Gate) or  Short Sword and Shortbow (Baldur's Gate: Enhanced Edition).
 * Short Sword,
 * Short Bow
 * 40 Arrows
 * 3 Potions of Healing
 * Oil of Speed
 * Wand of Magic Missiles.

Her level 1 Thieving Abilities are:
 * Classic: Open Locks 25%, Stealth 30%, Find Traps 30%, Pick Pockets 25%
 * Enhanced: Open Locks 25, Find Traps 35, Pick Pockets 25, Move Silently 35, Hide In Shadows 15

Dual-Classing
Imoen can be Dual-Classed to a mage anytime after level 2, however the 161,000 experience cap present in the expansion and Enhanced Edition creates a manageable cut-off point for re-obtaining Imoen's thief skills. A dual-class, by definition, must have its new class succeed the level of its old class by one level in order to re-obtain the benefits of the old class.

Imoen will become a level 7 Thief at 40,000 experience, which will still allow her to reach a level 8 Mage at 90,000 experience (130,000 exp total). This allows a significant investment in 2-3 Thief skills, primarily Lockpicking and Find Traps, as well as a third proficiency point, well placed in a Thief-specific proficiency like Long Swords. Therefore, it is suggested to dual class immediately after Imoen reaches level 7 Thief in order to not waste any earned experience, not to mention that it will match up canonically with next installment.

In-game biography
"When asked about her past, Imoen slaps your shoulder playfully. She says that you of all people should know, seeing as how you grew up together. Indeed, some of your fondest memories are of meeting this sprightly young lass. She apparently came to Candlekeep much as you did, though 10 years later in life, and she spent much more time with the gruff Winthrop than Gorion, "Puffguts" she would call him, much to the old innkeep's dismay. She seems the eternal child, and is quite content to play the part of little sister, though you are both of comparative ages. You can tell by her hearty smile that she will always be willing to travel with you, no matter what path you take."

Quotes
Note: Unlike other companions, Imoen has multiple instances of repeated one-liners.
 * (Selecting) "Yep?"
 * (Selecting) "Whatcha want?"
 * (Selecting) "Ha, ye're a queer fellow."
 * (Selecting) "I care not."
 * (Moving) "I am gone."
 * (Moving) "This way."
 * (Moving) "I've done had enough of this."
 * (Clicking) "Do you wanna tell me a story 'bout trollops an' plug tails? Please?"
 * (Clicking) "I know nothin' more, so leave me to go."
 * (Clicking) "Good on you if you save the day."
 * (Clicking) "Back home, Puffguts would always tell me a story."
 * (Attacking) "My blade will cut you down to size!"
 * (Fatigued) "-yawn- I'm gettin' a little sleepy."
 * (Idle) "Booooooriiiing!"
 * (Party leader) "Ye're all buffle-headed.
 * (Low health) "I feel so cold."
 * (Morale failure) Unknown
 * (Area; daytime) Unknown
 * (Area; nighttime) Unknown
 * (Area; town) Unknown
 * (Area; forest) None
 * (Area; dungeon) "'Tis something most unnatural here, and I want no part of it."
 * (Companion; death) "Poor sod, takin' the dirt nap so soon."
 * (Reputation; happy) "Good on you if you save the day."
 * (Reputation; unhappy) "Mutton-mongerin' riffraff."
 * (Reputation; angry) "I've done had enough of this."
 * (Reputation; breaking-point) "'Tis something most unnatural here, and I want no part of it."
 * (Reputation; post-break) "Well, good! You've changed since we were friends anyway. Not nearly as much fun now. Should have stayed in Candlekeep, instead of wasting time with you gulley pennies."

Baldur's Gate II: Shadows of Amn
At the start of Shadows of Amn, Imoen, who by now is a dual-classed Thief/Mage, has freed herself from capture, and very soon comes to the player character's rescue. When the player awakes, she tells him/her that they have been captured and tortured, but she doesn't know why. She relates something she overheard her captor saying: he want's to release the player character's 'potential', though it is not known what that means.

The player must escape the dungeon and may take Imoen with them or not. Whatever the decision, once outside, Imoen is back with the player in a cut scene in which Imoen attacks Jon Irenicus, their captor, with magic -- she has been tortured, and is frightened, but not knowing where they are, she does not know that the use of magic is forbidden without a licence in Athkatla. Because of this, Cowled Wizards appear and spirit Imoen and Irenicus away to an unknown location.

The first part of Baldur's Gate II: Shadows of Amn consists of the player gathering information and funds (with or without companions), and performing quests for the purpose of finding out where Imoen has been taken, and to gather the necessary resources to rescue her, which is eventually realised in chapter 4.

Bhaalspawn powers
By the end of Shadows of Amn, it becomes clear that Imoen is, much like Gorion's Ward, a Bhaalspawn. Following the defeat of Irenicus Imoen develops additional powers due to her newly discovered divine heritage. The changes improve her stats and add a number of innate spell-like abilities. All occur at a random time during gameplay:
 * +1 bonus point to Strength (raising it to 10)
 * +1 bonus point to Dexterity (raising it to 19)
 * Cure Medium Wounds
 * Draw Upon Holy Might

In-game biography
"Imoen chuckles when you ask her about her past, assuming you are just trying to keep her mind on happier times and places. She indulges you, and certainly does cheer up when speaking of how you spent your youths together in Candlekeep. She arrived there the same as you, in the company of your foster father Gorion, but despite this similiarity she grew up much more carefree than you did. Indeed, her lightheaded outlook has long kept her immune to the hardships of the world, though the dark confines and horrors of your current location have definitely taken their toll."

Quotes

 * "Aww, come on. I'm not cut out for leadership stuff."
 * "Easy as pie" (when pickpocketing)
 * "I'll stick by you no matter what, but we should still try to be decent to people." (when Reputation is low)
 * "I'm weak enough without my wounds. Someone give me a hand over here please." (when HP is low)
 * I'm getting sleepy. Wish we could stop for a bit." (when tired)
 * "I don't think I fit in with the people of the city anymore..." (when in city)
 * "I wish I could spend more time in the forest. It feels so alive." (when in a forest)
 * "Just like old times. Except for the torture and all that."
 * "My blade will cut you down to size!"
 * "Now I remember why travelling with you is such fun" (when Reputation is high)
 * "Now you see me, now you don't" (when hidden in shadows)
 * "Shh, its set and ready to go" (after successfully setting a trap)
 * "This place is too darn creepy. I really want out of here." (when in a dungeon)
 * "You can count on me!"

Personality
Imoen is a care-free, optimistic and cheerful character. She seems happy to have escaped the boredom of Candlekeep and eager to discover the world beyond the city walls. Imoen will try to joke around with the Gorion's Ward and almost any other companion in the group and lighten their spirits in the hardest moments to come.

In Baldur's Gate II: Shadows of Amn Imoen appears a bit worried and more mature, as she struggles with her newly-discovered Bhaalspawn heritage and the nightmares related to it. Nonetheless, she retains a great portion of her care-free attitude.

Imoen is also extremely attached to Gorion's Ward to the point of escaping the safety of Candlekeep to join their party, ignoring any attempts to be thrown out of the party when met in Baldur's Gate Chapter 1, looking the other way when the party's deeds destroy its reputation and never picking up fights with other party members, no matter how different their goals are. She can be seen as Gorion's Ward's guarding angel - always following them and looking over their shoulder.

Trivia

 * Originally Imoen did not exist in Baldur's Gate.  Her character was a late addition to fill a non-psychotic-thief gap in the early levels. There was no recording budget left, so her lines were scraped together from voice-over left from a scrapped demo. The original character was a guard named Pique. (confirmation needed)
 * The model for Imoen's Baldur's Gate 1 portrait was the wife of the team's lead terrain artist, Dean Andersen. (confirmation needed)