Hi, this is my guide for playing Nightmare Batman as the team's Jungle role.  He is an Attack Damage based Assassin, with not only some of the best clear times, but also sustainability of any Jungle champion in the game.


Mods/Augments
Mods - 5p10s Atlantis Gambit, +9 Attack Damage to Coda Blade, Lazarus 2 to Ra's Al Ghoul's Robes
Augments - Kai, Horsepower, Slasher, Laser (Basically Blue Beetle's basic Augments)

The mod to Atlantis Gambit allows you to gain a larger lead over most junglers, even if they run two gambits.  Your clears will be so much faster than their's, and with "successful" ganks, you should easily out money their Jungler even if you get killed early on.

The mod to Coda Blade is a pretty flexible slot, I take +9 to Coda since it's a cheap, fast building Item that provides tons of Damage, Penetration, and the ever valuable Wounding effect.

The mod to Ra's Al Ghoul's Robes allows you really get into the thick of teamfight in the mid to late game, and may even help aide in a post mortem Kill for you.

The augments I've chosen give Flat values for Attack Damage, and Attack Penetration.  I choose this, because Nightmare Batman is a very strong late game Champion, being able to sustain himself and lockdown enemies in teamfights.  The Flat value Augments allow you to get an early game boost, which in turn hastens your initial jungle clear time, helps in early Champion engages, and keeps on being worthwhile until level 8, by which point you should have used your Ultimate at least once to ensure a kill or assist.  This means you shouldn't be hurting in the credit department, and most of your damag will come from your items, not waiting for your Augments to scale into late game.


Ability Order

As a stealth initiating champion, you'll want to take a point into your W early anyway.  As a Jungler, you'll want that one point for extra damage on all drones in a Jungle's camp while you take down the Elite of that camp

After that point, you'll want to take a point into your E for faster Jungle clears, faster movement between camps/across the map, and more damage for your Ultimate when you get it.

The third point goes into Batarang.  This is really a preference, and if you prefer to go for level 2 ganks, your playstyle will decide if you want Movement Speed from your E, or the slow from your Q earlier.  Either way, by level 3 have both of them.

After this point follow this priority: Ultimate > E > Q > Passive > W

A lot of Nightmare Batman players take more points into their W earlier.  I prefer not to, seeing as every other ability and thing you do as this Champion scales with Attack Damage rather than Power Damage.  This ability order allows you to make the most of your items sooner rather than later.


Items

Start with 3 Health Vials, an Atlantis Gambit (mod'd for 5per10s gold), and a Marauder's Knife.  From here it's a preference that is determined by how comfortable you are managing your HP in the jungle.  If you are new to Nightmare Batman, or Jungling in general, I recommend taking Marauder's Knife to Rank 3.  If you are familiar with him, skip leveling Marauder's Knife at all, and go straight into Coda Blade.  This allows you to get into your main build faster, and grabbing Armor Penetration, and the ever important Wounding skill early on.  Code Blade is also a fantastic source of AD for the price.  Following Coda Blade, I normally build Promethium Mace until I can go into Deathstroke's Claymore.  The Attack Speed, and high Attack Damage on this item only serve to further abuse Nightmare Batman's passive Lifesteal (not to mention the gain from your Gambit).  If there's ever a point in the game where you have 500 extra credits, and are in a good position in game, upgrade your Gambit to rank 2, 5% extra lifesteal can make or break you staying alive.  After this, you usually have enough of a lead over your opponent, or enough damage to effectively trade with them.  This is when I go into Ra's Al Ghoul's Robes.  It's a fantastic defensive item, and allows you to possibly resurrect upon death.  The great synergy with Nightmare Batman however, is that even if they tick you down to half health while you're incapacitated from the item's effect, you can quickly regain health through your passive when you pop back up.

The rest of the item build is situational depending on what you're going against/your personal playstyle.  You may like taking Velo 9's and Joe Chill's for a crit build to lifesteal huge amounts, or would rather a more Power Damage Defense oriented build with Kryptonian Power Armor, or Sword of Beowulf.

Lobo's Chain should only be built if you're new to this game genre, or champions with Skillshots, you should be able to slow/keep up with em effectively through your Q and E.  Though if you're having problems with people getting away, Lobo's is never a terrible choice.


Powers

The listed powers, Cyborg's Teleport and The Joker's Detonate, are assuming you're playing with a coordinated team or at least someone who can help you with a leash or two pack strategy so that you do not have to blow your detonate on the first pack.  This allows an easy level 2-3 EMP grab after only 2-3 packs killed.  It's preferable to do it with your top laner, seeing as the bot support can also take Consume or Detonate to help with that EMP Creep.  The teleport is chosen mainly for it's gank potential, though at the start of the game it can be used to help secure both EMPs in a very short amount of time.  Always be mindful that The Joker's Detonate, while awesome at jungle clearing, is also a fantastic killshot/way to slow to ensure a kill if an enemy is about to slip away, and there is a drone or something else that is detonatable nearby (i.e. rock, dropped meteor, Star Sapphire's Predator, etc).

If you're newer to Nightmare Batman, or Jungling in general, I suggest taking both Nightmare Batman's Consume, and The Joker's Detonate.  This allows you more sustain in the jungle, and a hell of an easier time clearing your buff camps the first couple of go rounds through the jungle.  The consume is useful in late game teamfights situationally, as you can consume Star Sapphire's Predator, or any enemy drone nearby a fight to regen health instantly without having to back or get completely out of the fray.


If there's anything I missed, or if there's any questions about this build that you have please let me know.  You can contact me via twitch.tv/kirrx, or in game, HUG-Kirr.

Thanks for taking the time to read this guide, I hope it helps provide a new perspective into playing Nightmare Batman, or helps clarify things for those newer to the champion.