Quest

Quests are enchantments from Zendikar. These enchantments gain quest counters as triggered abilities for specific events. After building up enough quest counters, these enchantments yield rewards.

Cycles
Three cycles of Quests are featured in Zendikar:
 * Expeditions: A common cycle of quests that gain counters from Landfall triggers. An additional activated ability can be activated by removing three quest counters from the enchantment and sacrificing it. It includes Sunspring Expedition, Ior Ruin Expedition, Soul Stair Expedition, Zektar Shrine Expedition, and Khalni Heart Expedition.
 * Quests: An uncommon cycle that gains counters on events specified on the card. It has a similar activated ability to the Expeditions though the number of counters that needs to be removed varies. The cycle includes Quest for the Holy Relic, Quest for Ancient Secrets, Quest for the Gravelord, Quest for Pure Flame</c> and Quest for the Gemblades</c>.
 * Ascensions: A rare cycle that gains counters should a specific event have happened during a turn. However, no counters need to be removed to activate an ability. Instead, a static, triggered or activated ability is enabled after a threshold of counters is achieved. The cycle includes Luminarch Ascension</c>, Archmage Ascension</c>, Bloodchief Ascension</c>, Pyromancer Ascension</c>, and Beastmaster Ascension</c>.

Rulings

 * Not all quests have the word "quest" in their names.
 * Each quest has two abilities. The first ability triggers whenever a certain condition happens and puts a quest counter on the enchantment as a result. The second ability works only if there are a certain number of quest counters on the enchantment.
 * The second ability of each common and uncommon quest requires you to remove a certain number of quest counters from it and sacrifice it as a cost. You can activate this ability only if it has the appropriate number of quest counters on it, since otherwise you couldn't remove enough of them. Also, you may activate this ability only once, since you can sacrifice the enchantment only once. You can't search for two Equipment cards if Quest for the Holy Relic has ten quest counters on it, for example.
 * The second ability of each rare quest doesn't require you to remove any counters from it or sacrifice it. The counters and the enchantment will just stay put.
 * Once there are enough counters on a quest for its second ability to work, there's usually no particular need to add more counters to it with its first ability, though you are free to do so.