The players are able to battle against the bosses from Zombie Scenario Season 4. The host must have the Madness key to open this chapter.
A powerful key can be acquired under certain conditions. If a player holds one, they will be sent to a temporary nightmare where strong creatures await.
When in possession, you are able to host the extra Zombie Scenario Season 4 chapter, Madness. This key will deplete upon usage.
Defeat the zombie boss appeared in each round.
- You can buy and upgrade weapons by pressing the key in the shop area.
- Press the or keys to recover stamina and key to revive.
- If your team has been annihilated, you can use the Round Retry item by pressing the key as long as you or someone possesses the item.
- Surviving the round will result as money bonus. If not the case, you will receive a small amount as compensation, once your team has cleared the round.
- First Madness - Juggernaut
- Jim: Where am I?
- Jim: Here comes a huge guy, be ready! (After 55 seconds)
- Second Madness - Frozen Wrath
- Jim: It is not over yet?
- Gerard: A strong zombie is coming! All ready! (After 55 seconds)
- Third Madness - Savaging Gluttony
- Jim: What is this awful place? All hurry up and find the exit!
- Jim: What is that huge thing? It's coming here! (After 55 seconds)
- Fourth Madness - Neid & Zavist
- Jim: What a strange dream... Why are you here again?
- ???: I'll crush you, silly!
- Last Madness - Dr. Rex
- Jim: This is... Watch out for the traps in the room!
- Jim: That's really worse than the previous monsters, it's you again!
Madness was released on:
- South Korea: 6 November 2014.
- Taiwan/Hong Kong: 18 November 2014.
- China/Japan: 19 November 2014.
- Indonesia: 27 May 2015.
- CSN:Z: 17 December 2015.
- Madness is a state of frenzied or chaotic activity.
- Defeating bosses in this map does not increase the counter of [Wrath Controller], [Diet Controller], [Detective] and [Madness Terminator] medals.
- Host zombies make no appearance in this map, only origin zombies appear, except the Sting Finger (only host Sting Finger appears, no origin one).
- This is the first extra chapter which Ganymede does not appear as the main boss of Round 2.
- This is the first extra chapter that bosses don't appear in one arena together. Each boss arena is based on the one of each chapter in Zombie Scenario: Season 4 (except Round 1 and 2 are the same).
- In Taiwan/Hong Kong and Indonesia regions, there are few glitches such as sound looping or the fact that it is almost impossible to hit Frozen Terror when he's going to perform the Snowball Slam.
- There is a mistake of showing NPC message during the cutscene in round 2, which the texts show Gerard, but the image message shows Jim.
- There is a bug in round 1 which Juggernaut does not give any damage, only the zombies do so.