Hilde

Depressed

Middle row

Magic damage

Elves

Support

Phytoncide Wave

Unleashes a wave and recovers the HP of all nearby allies 1 time. Additionally, recovers the HP of 2 allies with HP lower than 80% every second.
■ Wave HP Recovery: Physical DMG: 21% of own Max HP
■ Continuous HP Recovery: 7.6% of own Max HP
■ HP Recovery Duration: 6s

Overtreatment

Activates Indiscriminate Treatment, dealing AoE Magical Damage to enemies. Allies within range become Giant and their Attack Speed increases.
■ Magical DMG per Hit: 670%
■ ATK SPD Increase: 87%
■ ATK SPD Increase Duration: 9.8s

Passive

Removes all Status Effects on an ally within the designated range.
■ Cooldown: 12s

Normal ATK

Basic: Fires her Syringe Gun, dealing Magical Damage to the enemy.
■ Magical DMG: 100%
Enhance: Recovers the ally with the lowest HP Ratio in lieu of her third attack.
■ HP Recovery: 20% of own Max HP

Skill priority

You will level up most skills regardless how useful they are for the combat power padding in endgame. As a general rule of thumb:

Units you are not sure you will use long term: Skills to level 4. If they're passives that benefit the team, can take that to 7.
Strong units but not your main personality: Skills to level 7 for raids and elemental content. Not worth going higher if they are not your main team.
Strong units on your main personality (and waifus): Max out skills. You can start with 7/7/7 and slowly work towards 12/12/12 when you can sweep stage 10.

Recommended artifacts

Artifacts and runes will always change depending on the stage and content you are currently facing, this is just a couple of examples on what items work for this Apostle.

Legendary