To become priest in Laplace you must have faith and discipline, priest support party members through chanting support spells. Holy Templar have godly offense and defense while Spirit Bishop can heal people.
Laplace Priest
Recommended stat points - Faith and Constitution.
Recommended attributes - HP and Defense.
Recommended weapons - Staff, Sword and Shield, and Halberd.
Recommended equipment - Plate and Leather.

Holy Templar vs Spirit Bishop
When crusaders understand that they can't protect everyone with just support spells they become Holy Templars. Holy Templars can taunt enemy and even receive incoming damage instead of the party members. Spirit Bishop can recover SP, HP and even increase resistance.
Laplace Priest gameplay
Laplace PriestPriest skills -
Icon Name Lvl Cooldown Description
Laplace Priest skill
懲戒天閃 4 8 seconds Call heaven Light and damage enemy.
Laplace CrusaderCrusader skills -
Icon Name Lvl Cooldown Description
Laplace Crusader skill
奮勇真言 12 10 seconds Aura. Each attack increase your threat (can be wrong) and decrease your team members threat. (Threat = Aggro) Only one aura can be activated at a time.
Laplace Crusader
聖光術 12 6 seconds Removes Status Effect (and Heal?) from allies (can be wrong)
Laplace Crusader sp
精神集中 20 10 seconds Aura. Increase party members SP recovery rate. Only one aura can be activated at a time.
Laplace Crusader damage
驅靈殿堂 30 120 seconds Light damage spell and Removes Status Effect (and Heal?) from allies. 
Laplace Holy TemplarHoly Templar skills -
Icon Name Lvl Cooldown Description
Laplace Holy Templar skill
堅韌信仰 40 10 seconds Aura. Increase party members defense and resistance. Only one aura can be activated at a time.
Laplace Holy Templar aggro
正義引力 40 30 seconds Pull and taunt all enemies to you.
Laplace Holy Templar threat
聖光霸體 45 30 seconds Threat-generating skill, damage all enemies around you increase threat by a lot.
Laplace Holy Templar sacrifice
奉獻之身 50 10 seconds Aura. Act as a shield to protect teammates and receive incoming damage instead of them. Only one aura can be activated at a time.
Laplace Holy Templar shield
戰神聖盾 55 120 seconds Gives his teammates a damage reduction shield,
laplace spirit bishopSpirit Bishop skills -
Icon Name Lvl Cooldown Description
laplace spirit bishop
驅魔聖十字 40 30 seconds AOE attack.
laplace spirit bishop revive
生命禱告 40 20 seconds Revive (?) spell.
laplace spirit bishop increase attack
神火之照 45 30 seconds Improve teammates attack (physical and magical) and recover SP.
laplace spirit bishop resistance
天使領域 50 30 seconds 迎接遠古天使降臨,強大的防禦及恢復能力令隊友能夠無後顧之憂。
#持續時間內提高範圍內的隊友全抗性,並每幾秒內發動一次連鎖治療
#在時間內對範圍中的隊友附加增益狀態 Something about resistance and AOE heal.
laplace spirit bishop aoe heal
療癒真言 55 120 seconds AOE Heal (?)