|Class||Wizard 1 / Rogue 1|
|3||Wizard||Accomplished Sneak Attacker||Grease, Reduce Person||–|
|5||Arcane Trickster||Precise Shot||Mirror Image, Sense Vitals||–|
|6||Arcane Trickster||–||Haste, Slow||–|
|7||Arcane Trickster||Greater Spell Focus: Transmutation||Displacement, Heroism||–|
|8||Arcane Trickster||–||Obsidian Flow, Greater Invisibility||–|
|9||Arcane Trickster||Weapon Focus: Ray||Dimension Door, Confusion||–|
|10||Arcane Trickster||–||Baleful Polymorph, Echolocation||–|
|1||Str 10, Dex 17, Con 8, Int 19, Wis 10, Cha 14|
|Mobility (max)||Trickery (max)||Stealth (max)||Knowledge (Arcana) (max)||Knowledge (World) (max)|
While Regongar is essentially a Fighter/Mage, Octavia fits another timed-honored CRPG niche - the Thief/Mage. Or, in modern parlance, the Rogue/Wizard. As far as her niche goes, Octavia excels, having a high Dexterity and Intelligence score, giving her both acceptable ranged prowess and potent spells, respectively. She also starts with the Point-Black Shot and Spell Focus: Transmutation feats to further reinforce these areas of expertise, as well as with Skill Focus in Trickery, all of which are fair choices.
Octavia’s major downsides are the fact that she starts with a generic level in Rogue rather than the superior Thug subclass and a wretchedly low Constitution score, which will result in her having about half the Hit Points of the next weakest character in your party. She’s exceptionally fragile and will tire quickly while you’re exploring, which means you’ll have to babysit her during combat and rest frequently out of combat. She’s also not much of an archer in the long-term, as her Base Attack Bonus is abysmal. Fortunately this isn’t a huge issue, as she’ll perform much better just using ranged touch attacks thanks to her Sneak Attack damage.
If you decide to bring Octavia with you, you’re better off trying to make her the best version of the Rogue/Wizard archetype she can be, despite her limitations. Of primary importance is her progression as a Wizard, which means you want to ensure she at least attains the ability to cast 9th-level spells, a feat that requires you to hit the equivalent of 17th-level as a Wizard. Fortunately leveling as an Arcane Trickster and Eldritch Knight will both enhance her spellcasting abilities as if she were leveling up as a Wizard while granting other bonuses, making it an ideal course of action.
Arcane Trickster will net you +5d6 sneak attack, and Impromptu Sneak Attack, which will allow you to negate the Dexterity Bonuses a creature adds to its Armor Class for up to four rounds per day, while Eldritch Knight will score you some much needed Attack Bonus and Hit Points. Sink some levels into Wizard, boost your Trickery and Stealth until they’re both Rank 4 (you want to max these with Octavia, anyways) snag the Accomplished Sneak Attacker feat as soon as possible and by 5th-level you should slip into Arcane Trickster, there to remain until that class maxes out after ten levels. During this time, make sure to grab Martial Weapon Proficiency - you won’t use it, but you’ll need it to unlock Eldritch Knight, which you’ll advance in through the end of the game.
As far as gameplay goes, Octavia is fairly simple. Drop the bow and just use ranged touch attacks like Ray of Frost. Use illusion spells to protect Octavia in combat, and don’t worry too much about spell selection - as a Wizard, she can learn new spells off scrolls She’ll ultimately continue progressing as a transmuter, which will improve the DCs of her Slow, Baleful Polymorph and Disintegrate spells, among others. Disintegrate deserve special mention, as it’s a potent, high-level ray spell that’ll become one of Octavia’s more reliable ways of dealing heavy damage when the need arises.