WIZARDRY8コミュのNPC list

Myles: Male Higardi Human Rogue, Level 5. Fountain in Arnika, or Rapax Castle.
Vi Domina: Female Higardi Human Valkyrie, Level 6. Shuttlewreck in Arnika.
Madras: Male Trynnie Gadgeteer, Level 8. Madras's observatory in Trynton Upper Branches.
Tantris T'Rang: T'Rang Samurai, Level 6. T'Rang outpost in Marten's Bluff.
RFS-81: Android Trooper, Level 10. Hut in Mine Tunnels.
Private Sparkle: Trynnie Ranger, Level 6. IUF Recruitment Centre in Umpani Base Camp.
Saxx: Umpani Bard, Level 8. Yamo's Roadhouse in Umpani Base Camp.
Sergeant Glumph: Umpani Fighter, Level 11. Bayjin.
Urq: Mook Psionic, Level 9. Arnika.
Drazic: T'Rang Ninja, Level 14. Rapax Away Camp.
Rodan Lewarx: Umpani Lord, Level 14. Rapax Away Camp.
Sexus: Rapax Mage, Level 18. Rapax Castle.

となっております

Myles さんが or Rapax Castle てのは未確認です
攻略ルート、必要アイテム、同盟選択の如何などにより同行できる状況は違います

Vi さんはクリア時に同行させたいので、準必須メンバーですが、海の中やラパックス城へは行くのをいやがります