Orchidna’s Disciple is name of unique title that is going to be removed with upcoming skill patch. Abyssal skills, as we know them, will be replaced by one skilltree so this title, will be unobtainable.
Effect of Orchidna’s Discipletitle is decrease of mana cost for combat skills -5% and decrease of cooldown for Abyssal skills -9%.
How to get Orchidna’s Disciple title? You need to complete achievement that requires all Abyssal skilltrees on level 55.
For every Abyssal tree you need one Specialization Snowflake (200g at General Merchant) and 48 Abyssal Crystals in total.
Snowflake is used to obtain new skilltree. Leveling skilltree from 19 to 20 requires 3 Abyssal Crystals, from 39 to 40 it requires 15 Abyssal Crystals and finally to get from 54 to 55 you need 30 Abyssal Crystals.
It is also possible that Orchidna’s Journals (books that are obtained by unlocking Abyssal skilltrees) will be removed as well. Hovewer, I cannot confirm this now.