Helms are classified based on their rarity: Common, Rare, Epic, Legendary and Unique. The higher the rarity, the better the helm (they have higher upgrade value, better shadow abilities, more perks can be attached to them, they deal more shadow damage and take less head hit damage in event fights). Common helms do not have Shadow Ability but carry one slot. All Rare helms of a faction share the same Shadow abilities and carry one slot. Epic, Legendary and Unique helms come with unique Shadow abilities and carry two slots for Epic, two perk slots for Legendary and Unique.
Helms can be bought from the store. Otherwise, they can be obtained from chests, booster packs, dropped randomly from main quest fights, marathons, battle passes or be purchased from offers. If the players receive a helm that is already owned by them, a part of an upgrade bar fills up. When the upgrade bar fully fills up, the helm gets upgraded and a number of Shadow Energy is given to the player. Better chests and booster packs may contain helms with higher rarity. As for the drops from opponents, the players may obtain helms with random rarity; it is possible to get a helm with Epic or Legendary rarity, but the chance is small.
Premium helms (e.g. Basilisk's Gaze or Eye of Time) only can be obtained from a specific event's battle pass or ingame offers and they're cannot be obtained from regular booster packs or chests.
Some helms belong to some equipment sets, which give a fight bonus when fully equipped. When the player collects a certain set for the first time, they can get a reward. The reward for each set can only be obtained once.
Special helms are limited-time helms that can only be obtained from marathon. They are only available during special events. Once obtained, special helms will stay with the players even if the event is already over. Their rarity is classified as Unique and they come with 2 slots.
During the tutorial, the players receive and must equip the Visored Casque while being instructed regarding equipment usage.
V.O.A.K. is an abbreviation for the phrase: "Visor of Absolute Knowledge".
Ataraxia carries the Eruption Shadow Ability, just like all Epic, Legendary & Unique Heralds Helmets, however, it slightly carries the Uppercut Shadow Ability, just like all Epic & (some of) Legendary Legion Helmets if you fully equip the Future Keeper Set.