Cleric

Mechanics

There are a few things to consider when playing a Cleric, and a few things you need to be aware of.

Clerics are the most powerful, and only dedicated healing class in the game. 
The healing effect of Hallowed Ground does not stack with itself, whether its your own from the Holy Regalia or another players. A player can only be under the effect of one Hallowed Ground at a time, and the strongest takes president, not the most recent.

Due to the strength of the Clerics healing potential, there is a lot of room for variability within your setup, and at later levels you will be prioritizing items that help support and buff the group rather then items to improve your own abilities; Midas' Pendent, Towering Shield, and Hammer of Zeus are prime examples of this.

Attribute points should be spent in approximately a 1 Strength : 1 Agility : 3 Intelligence ratio. 

Ultimately you want ~750 base Strength, ~750 base Agility and ~2000 base Intelligence in order to achieve 20-25,000 health, and ~1100 total agility, as required for 100% uptime on Transcendence.

For your familiar skills, you want to invest in the 5% Spell Power buff from Aptitude and your preference of 75 Strength/Agility/Intelligence from Gift of Endurance/Dexterity/Wisdom, to achieve the Agility and Strength breakpoints above.

At max level, the core setup is                            , combined with your choice of Olympian Relic;

1.      Towering Shield of Athena - Objectively the best starting relic, incredible damage mitigation, AoE armor buff, and a on-use effect to fully heal and replenish the mana of yourself, and all nearby players. 

2.    Thundering Hammer of Zeus - Once you're more comfortable healing Hyperion and have some more stats under your belt, this often becomes your go-to relic, as Tanks will often have Towering Shield of Athena for the AoE armor buff anyway. Zeus increases your damage, in-turn increasing your Transcendence healing, whilst increasing the group's damage and reducing your targets armor. 

3.      Searing Flame of Prometheus - Searing Flame technically does provide the best personal output, however Cleric's healing potential is so strong there is very little point in using this, and you are far better off using items such as Towering Sheild of Athena and Thundering Hammer of Zeus to provide greater group buffs.

>>Blanket Disclaimer: You, and every other player will need items from all crafting professions so there is no 'best' profession for any given class. If you are selfishly looking for personal enhancements, Alchemy is the only profession whereby you can't bring items you crafted through to another game, so this might be the best choice on a personal level, but increases dependency on others for crafting<<