The Challenge mode is best thought of as a much tougher, gauntlet-style counterpart to Quest Mode. In this mode, you participate in battles that conclude with a boss fight. Successfully defeating this boss will win you, among the usual rewards like Gold EXP, a hero fragment of the defeated boss that you can eventually exchange for a rare hero or above at the Divine House once you collect enough.
You can participate in a Challenge stage five times a day, but each battle will only count towards your quota if you win. In other words, you can participate in and win a battle five times each day, but there is no limit to the number of times you can lose.
Just like in Quest Mode, defeating a stage in Challenge Mode with a 3-star rating will allow you to raid that specific stage so long as you have enough Stamina.
Blood Moon
Contract
Reward: BloodDemon Rin Fragment x1 (3/3 Star)
Peaceful Return
Reward: Princess Nina Fragment x1 (3/3 Stars)
March On
Reward: Insane Rick Fragment x1 (3/3 Stars)
Temporary Retreat
Reward: Monk Dagan Fragment x1 (3/3 Stars)
The Leader!
Reward: First Mate Kate Fragment x1 (3/4 Stars)
Nun and Knight
Reward: Battle Riya Fragment x1 (3/5 Stars)
Trapped
Still Human
Reward: Phoenix Fragment x1 (3/4 Stars)
Dragon
Reward: Wood Dragon Fragment x1 (3/4 Stars)
Wrathful Retribution
Reward: Thunder Fragment x1 (3/4 Stars)
2 Against 2
Reward: Hell Elegy Fragment x1 (3/3 Stars)
Sword Kiraeld Combo
Reward: Disciple Eagle Fragment x1 (3/4 Stars)
War Maiden
Reward: Sinner Pep Fragment x1 (3/4 Stars)
Heroic Dawn
Reward: Swordsman Dawn Fragment x1 (3/5 Stars)
Secret Tower
The Escaped One
Reward: Archangel Yuri Fragment x1 (3/4 Stars)
Berserk Mountain Man
Reward:Golem Fragment x1 (3/5 Stars)
Duel of Sorcerers
Reward:Recorder Gary Fragment x1 (3/4 Stars)
Invisible Sword
Reward:Water Dragony Fragment x1 (3/4 Stars)
Treasury Guard
Reward:Sorcerer Rogge Fragment x1 (3/4 Stars)
Unify with Tower
Reward:Humanoid Nana Fragment x1 (3/4 Stars)
Awaken Linda
Reward:Maid Linda Fragment x1 (3/5 Stars)
Witch Hunt
Formation
Reward:Worshipper Eagle Fragment x1 (3/4 Stars)
Eye of God
Reward:Knight Owl Fragment x1 (3/4 Stars)
Fire Stopper
Reward:Addict Oxi Fragment x1 (3/4 Stars)
Iron Wall
Reward:Knight Shilda Fragment x1 (3/4 Stars)
Heart Kiraeld
Reward:Demon Medusa Fragment x1 (3/4 Stars)
Valley Battle
Reward:Sacred Horos Fragment x1 (3/4 Stars)
Hell on Earth
Reward:Sacred Zinc Fragment x1 (3/4 Stars)
Dark Tower
Reward:Traveller Anna Fragment x1 (3/5 Stars)
War of Red Door
Abandoned Sea
Will of Greatness