As a Cleric, Shadowheart is capable of casting spells, healing and buffing allies, and tanking damage for her party. Her subclass is Trickery Domain, allowing her to cast a variety of stealth and illusion magic not normally available to Clerics.
Shadowheart is first encountered on the Nautiloid during the Prologue, trapped inside a Mind Flayer pod. She can be freed by interacting with the nearby console or using certain class-restricted dialogue options on the pod. If she is freed, she will join the party as a temporary companion. Upon escaping the Nautiloid, she leaves the party.
Shadowheart is encountered again a second time at the Ravaged Beach inside the Wilderness. If she was freed from the pod during the Prologue, she will be unconscious on the ground and wake up when interacted with. If she was not freed, she will instead be found attempting to gain entry to the nearby Dank Crypt. Either way, she can be invited to join the party after speaking with her.
If Shadowheart is not interacted with at the Ravaged Beach, she will move to the Druid Grove on her own in search of a healer. She can be spoken with there and invited to join the party.
Background
A loyal cleric of Shar, Shadowheart is the sole survivor of a holy mission undertaken on the Mistress of the Night's behest. She alone must deliver a relic of immense power to her coven in Baldur's Gate, while threatened by a strange new magic that is burgeoning from within.
Shadowheart is guarded and hesitant to reveal information about herself, her motives, or the relic she carries. She displays a particular distrust of Githyanki such as Lae'zel. Often, she seems indifferent to the plight of others; however, she does not explicitly take pleasure in their suffering, and will disapprove of unnecessary cruelty and violence. She will usually approve of finding non-violent solutions to situations, and treating animals and children with compassion. Above all, Shadowheart values pragmatism.
Interactions
Approval
Shadowheart likes finding pragmatic and efficient solutions to problems. She appreciates discretion, privacy, and open-mindedness. Shadowheart generally responds well to acts of heroism.
The following story and dialogue choices will cause Shadowheart to gain approval.
Successfully persuade Varsh Ko'kuu to let you take the githyanki egg and suggest you'll take it to a better Creche or raise it yourself.
If Lae'zel is chosen to use the zaith'isk, succeed a difficult persuasion or Wisdom check to have her get out of the it before it harms her
If Lae'zel is chosen to use the zaith'isk, succeed a difficult deception check or a Wisdom check followed by a persuasion to have her get out it' during the second phase Will permanently lower Lae'zel's INT by 2.
If Lae'zel is chosen to use the zaith'isk, succeed a difficult deception check or a Constitution check followed by a persuasion to have her get out of it during the third phase Will permanently lower Lae'zel's INT and WIS by 2.
At the next long rest after the events at the Crèche, encourage Lae'zel to listen to Kith'rak Voss or make her own choice when he visits the camp and speak about the Mysterious Artefact.
Use Persuasion to successfully convince her to explore the illithid powers.
Shadowheart dislikes those that disapprove of her worship or people pressing her for answers or details. She does not like needless cruelty or violence and can respond unfavorably to being too open with untrustworthy or unknown individuals.
The following story and dialogue choices will cause Shadowheart to lose approval.
When she has the odd magical flare-up, ask if it was some form of Sharran magic.
Insist on continuing to use the tadpole's power after the second dream.
At the next long rest after the events at the Crèche, encourage Lae'zel to kill to Kith'rak Voss when he visits the camp and speak about the Mysterious ArtefactThis leads into a very difficult optional boss fight.
Letting Volo follow through with his attempt to remove the parasite
Romance Spoilers This section reveals details about romance and may contain mature themes.
In Chapter One, Similarly to other characters, her first important romance scene will be unlocked during the Party by proposing to have a drink in private with you. Shadowheart will only propose it to you if you sided with the Tieflings and if you have at least medium approval. You'll meet her away from camp later that night, where you will have a deep conversation. After some dialogue, the camera fades and returns a few hours later showing both of you laying on the ground, holding hands. You can choose to kiss her, and then both will return to camp.
Next day, you can have a conversation with her regarding the previous night. Her dialogue will depend on her level of approval.
According to Larian Studios, until Patch 3, Shadowheart was the most romanced female companion and the second most romanced companion overall.
The cantrip selection Shadowheart has in the beginning is very sub-optimal, which can be frustrating, especially to newer players who may not understand why:
As the Fire Bolt cantrip Shadowheart starts with is a high half-elven racial spell, its attack roll bonus scales off intelligence, an ability Shadowheart is not specialized in. This makes the hit chance of this version of firebolt very low in Shadowheart's hands.
Her other cantrip, Sacred Flame is not an attack cantrip, but rather a saving throw cantrip, This means it is not helped by the various bonuses and advantages an attack would enjoy (High Ground Rules, Advantage from hidden attack, etc). Furthermore, it is a dexterity save cantrip, and dexterity is an ability many enemies are decent at.
The best way out of this situation is to pick up a better offensive cantrip elsewhere, either by picking Produce Flame when at cleric level 4. Or finding equipment that grant offensive cantrips (in such cases Shadowheart's natural Spellcasting Ability, Wisdom, is used instead)
And since her Strength and Dexterity isn't high either, early on her best offensive option is likely to be Guiding Bolt while at range, and Inflict Wounds while up close. Both of course costs spell slots.
She can also indirectly contribute to the party's damage output via Bane and Bless, the former making the affected enemies 10% more likely to get hit, the latter making the affected allies 10% more likely to land a hit. Note that bane requires its target to fail a saving throw to take effect so it is somewhat less reliable.
These are both Concentration spells however, so there is a risk in using these. make sure Shadowheart is safe from damage if this is the option chosen. Also note that only one Concentration spell can be maintained at a time by a single caster.
Finally, Create Water confers the Wet Condition to the affected targets, making them vulnerable to cold and lightning damage, meaning they will take double damage from those damage types. This also potentially creates a harmful surface for the party's enemies.