Combo Demon Hunter is a midrange and combo hybrid Demon Hunter archetype.
History
This deck was centered around the synergy between 
Kael'thas Sunstrider and 
Twin Slice. Playing the original 0 mana Twin Slice and Second Slice triggered Kael'thas, allowing the Demon Hunter to cast 
Inner Demon for free. Doing this twice allowed for a total of 20 burst damage, which could be stacked further by Chaos Strike or weapons like Aldrachi Warblades and Warglaives of Azzinoth. While this usually wasn't enough damage to outright kill the opponent, the rest of the deck focused on pressuring the opponent, keeping their health low enough to finish off, or having enough damage left over to end the game after the combo had been used. The deck also used Altruis the Outcast to potentially add lots of damage.
The archetype achieved this combo by very rapidly digging through the deck, thanks to neutral draw and demon hunter's naturally strong draw cards. The 20 damage combo could initially be done for only 6 mana, meaning a good hand could end the game early. Since the deck is emptied so quickly, some decks used 
Zephrys the Great to clean up should they not have enough damage for lethal.
The deck was hurt significantly in Patch 17.0.2.45932, which raised Kael'thas from 6 mana to 7 mana and Altruis from 3 to 4 mana. While still viable, the deck fell to the wayside with a faster meta and more efficient aggro and tempo builds for demon hunter. However, the nerf in Patch 17.4.1.51510 buried the deck entirely when Twin Slice and Second Slice were increased to 1 mana each, making the full combo impossible to perform without prior mana reduction.
A new variant of Combo Demon Hunter was introduced by Madness at the Darkmoon Faire with the addition of 
Il'gynoth. This variant focuses on using Il'gynoth's ability to kill enemies in one turn with Lifesteal cards, either using large attack buffs stacked onto Aldrachi Warblades or with spells empowered by Mo'arg Artificer.
Common cards
The following cards are usually in the deck.
Core cards
The following cards are played in most or all versions of the deck:
Il'gynoth Variant
Optional cards
The following cards are played more than occasionally, but not always:
Wild cards
Wild cards that fit well into this deck type:
Please add any available information to this section.