Here is the full list of all 13 Legions of Tyrandel achievements.
Win an online game using Valkyrie
Win an online game using Leviathan
Win an online game using Humbaba
Win an online game using Fenrir
Win an online game using Izulu
Win an online game using Arion
Win an online game using Emperor Jimmu
Win an online game using Sphinx
Win an online game using Grootslang
Complete all tutorials
Complete all puzzles
Complete all missions
Build a deck from scratch