From all dungeons will drop twice as many tokens. This means that silver chests rewards two tokens, gold chests reward four, and ancients reward six. The drop rate of those tokens do not increase. Specifically, the chances of getting Silver, Gold, or Ancient chests remain the same before and during this event.
The first occurrence of this is event is on Thursday November 19, 2015 to Monday November 23, 2015. From that point onward, the event occurs during special occasions, with different expiration times.
Notes and Tips
Using gems to refresh dungeons during these particular events will help accelerate your token gain.
Other events that currently add a multiplier to token count will be added on top of this event. For example, another Hero bonanza event will multiply the total count by x4. Tokens like Lupina or Julius found in Amazing chests are also doubled during this event.