Edit: This issue has been solved in version 19.

There is currently incorrect information on the tooltip text regarding Hero Class Emblems. Currently, it is not possible to gain Emblems from the Alliance War loot nor Rate Titans. You can gain Emblems from Class Quests, Alliance War Chests, Wanted Missions and Rare Wanted Missions. 
We’ll be correcting the Emblem tooltip texts to reflect the current situation.

Please note that we will be adding Emblems as possible rewards for Rare Titans and VIP Pass in the upcoming versions (ETA: version 19).

Our apologies for any inconvenience caused by this issue!