Recommended gem level for doing any drow challenge is e90+
Drow Challenge 1:
Organized Crime
"The mysterious drow wish for you to prove your murderous honor to them."
Requirements: Demon as Base Faction, Drow as Prestige Faction, Reincarnation 6+, Perfect Combo upgrade purchased, Goblin, Demon and Undead challenge 1 completed.
Challenge: Have Honor Among Killers with at least 500 trophies and 1000 Royal Exchanges bought.
Effect: Increase Royal Exchange bonus by 0.025% per trophy you own.
Upgrade: Works with Demon+Drow
Tip: Use Elven Bloodline.
Drow Challenge 2:
Dark Elegance
"The Spider Queen is not pleased with some of her worshippers. You must weed out the weak and sacrifice them at the temple altar."
Requirements: Goblin as Base Faction, Drow as Prestige Faction, Reincarnation 11+, Drow Bloodline, Goblin, Demon and Undead challenge 2 and Drow challenge 1 completed.
Challenge: Build 2000 Spider Sanctuaries (Dark Temples).
Effect: Increase the production of all buildings based on faction coins earned this game.
Formula: log^2(1 + x), where x is your Faction Coins Gained (This Game) stat.
Upgrade: Works with Goblin+Drow
Drow Challenge 3:
Sorcerer's Pact
"A legion of interlopers have invaded our sanctuaries. Work yourselves into a rage and tear them apart."
Requirements: Undead as Base Faction, Drow as Prestige Faction, Reincarnation 21+, 1750 excavations, Goblin, Demon and Undead challenge 3 and Drow challenge 2 completed.
Challenge: Have at least 2 hours of activity time for both Blood Frenzy and Combo Strike.(This Game)
Effect: Online Time (This game) is added to Offline Time (This game).
Upgrade: Works with Undead+Drow
Tip: Run both spells at the same time, depending on mana regeneration it takes about 1 hour 15 minutes to complete the challenge.
Drow Challenge 4:
Trained Assassins
There is a civil war between 2 Spider Gods. Bolster our forces and wipe the weaklings off the face of the realm.
Requirements: Any Evil as Base Faction, Drow as Prestige Faction, Reincarnation 27+, 2000 excavations, Drow Challenge 3 completed.
Challenge: Cast Call to Arms with at least 35,000 buildings.
Effect: Increase your Offline Time (This Game) based on spells cast in this R.
Formula: (8 * log10(x) ^ 4) where x is spells cast in this R.
Upgrade: Works with any Evil+Drow
Drow Challenge 5:
Shadow Mirage
It is time to emerge from the shadows. Our warriors will demonstrate their hard work and lead us to domination of the realm.
Requirements: Any Evil as Base Faction, Drow as Prestige Faction, Reincarnation 33+, Drow Unique Building, Drow Challenge 4 completed.
Challenge: Have at least 2 hours offline (This Game) and at least 360 charges of Combo Strike.
Effect:A fraction of your alignment spell bonus is applied passively.
Note: "Fraction" is equal to 5%.
Upgrade: Works with All
In-Game Challenge Final Reward
Spell Upgrade Versatile Combo
Increase Combo Strike counter based on the amount of spells cast in this game, not including Tax Collection.
New Combo Strike Counter Formula: x + y, where x is your Combo Strike cast count and y is every other spell (except tax collection and generic) cast count.
Effect: Also increases offline spell cast amount by multiplicatively based on your offline mana regeneration.
Formula: (10 * log10(1 + 30)).