The best class for Julei: High Cleric (Lumina)

Key Stats
Spirit, Stamina
Julei: High Cleric Details
As the last character to join your party, Julei fills a niche that your gang has likely struggled to fill until now: Healing. And of all the classes Julei can pick, High Cleric is the healer-est of them all. With a sky-high Spirit stat and a buff that doubles the healing potential of Julei’s moves, the little sproutling will become easily capable of topping off a party member’s HP with a single spell. But really, because High Cleric gives Julei his most foundational healing and status recovery spells, you’ll want to invest in this class no matter how you build Julei.
Once Julei does unlock his third tier of skills in his Elemental Plot, the Healing Light + spell massively elevates his usefulness. The ability to functionally heal the entire party’s HP in a single cast is borderline essential for the game’s hardest challenges, and the Strong Roots skill will help him survive one fatal blow per battle. I highly recommend giving Julei resistance to status ailments and strong defenses so he can always bring your party back from the brink.