This achievement can be obtained by completing seasonal events and do all quests that are required during the whole year. For each season (Winter, Spring, Summer, Autumn) there is a certain event that is similar to the holidays in real life. All events have specific dates and limited time.
To Honor One's Elders can be done during Lunar Festival Holiday (Jan 24 - Feb 7)
Noble Gardener on April 13 - April 19
The Flame Warden(Alliance)/Keeper(Horde) have to finish Midsummer Fire Festival (June 21 - July 5)
Hallowed Be Thy Name during Hallow's End (October 18 - November 1)
Fool For Love in Love is in the Air (February 8 - February 21)
For the Children during Children's Week (May 1 - May 8)
Brewmaster in upcoming Brewfest (September 20 - October 6)
Merrymaker in the coming Feast of Winter Veil (December 16 - January 2)
Reward that you will receive is Reins of the Violet Proto-Drake.
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