The Crusade is part of the Time Portal building and comprises of 9 different stages to complete on a daily basis.
Only level 30 heroes or higher can participate.

The health of heroes does not reset during a crusade, and any that die during a battle will be eliminated from continuing. You can however revive them using Life Orbs, at the cost of 100 diamonds.
The difficulty of it will scale depending on the power of your heroes.
Rewards
Each stage will reward either Battle Coins or Hero Fragments.
Every 3 stages completed will reward a Chrono Star for the Time Portal building.

Where can i find that crusade shop?
Sorry, that was removed when they added the Time Portal building recently. The guide has been updated.
I can’t find crusade shop
crusade shop?????
where?
what do I do with my crusade coins?
how about dead heroes on labyrinth. cant continue level 4. how to revive all dead heroea?
How to revive all dead heroes on labyrinth? cant continue on level 4 stage. anyone have idea?