I'm guessing Karlach is likely a bard, based on the look of her gear. KInda also fits her snarky mouth. A barbarian is also possible given she is a Zariel Tiefling, but that would be a waste, honestly, since Tieflings are innate casters and barbarians can't cast while raging. A Barbarian is also unlikely to start with a crossbow, but the class kinda fits her dialogue about the war in Avernus.
Just a thought on (implicit) alignments, keeping in mind the current companions are mostly evil/ neutral and coming ones are likely good: Astarion: Chaotic Evil (Vampires are usually lawful evil, but this fits better on a rogue running away from his master) Lae'zel: Lawful Evil (as are all Gith) Shadowheart: Neutral Evil (as is Shar) Gale: Lawful Neutral (he seems the least evil of all current companions, imo) Wyll: Chaotic Neutral (he loves kids and has a revenge story; seems like a standard renegade) Minsc: Chaotic Good (known) Karlach: Neutral Good (hard to believe, considering she is a tiefling with a snarky mouth, but maybe? Or maybe Chaotic Neutral (most Tieflings are Chaotic)? Note that bards are almost always neutral along at least one dimension) Helia: True Neutral (for a Shapeshifter Druid) or Chaotic Good (a Selunite lycanthrope; would be an interesting dynamic with Shadowheart) or Chaotic Evil (a Malarite lycanthrope; highly unlikely given she was being bullied by kids)
