Why Nightmare Robin on Coast City?: He is a very high output assassin you has CC built into his kit. End game he can destroy a marksman or blaster before they deal any damage to him. 

Damian is here to rule the night much like his father before him.

First, let's cover the mods. I run Enhanced Marauder Knife, Enhanced Deathstroke's Claymore, and Enhanced Coda. This is just so I have a maximum damage output to snowball from early. 

The Build: I start with T2 marauder knife and 3 health pots. I build the knife to T3 before taking Coda Blade. Build this up to T3.

Once you get T3 Coda move onto Claymore T2. Around this time, you may want to slowly start putting levels into Lobo's Chain. Once you max Claymore, build up Lobo's Chain. You will benefit greatly by having some bonus health, and an extra slow to help secure a kill. Now, you can build Atomic Axe if they are stacking Armor, or move onto an optional item if they are not. If for some reason your enemy has a very low attack armor total, don't build Atomic Axe and move into an item combo like Crossbow and Utility Belt/Time Pack.

Jungling: In Coast City you will jungle in a triangle pattern sharing the middle large drone with your fellow jungler before/after you capture your team's relay. For more info on jungling, check out my main Coast City guide, or Soundbyte's jungle guide. The later is a little outdated, but it still has a lot of great info in there. 

Ganking: Target the weakest, most exposed enemy champion in lane. Gank using Q to knock them down, E to jump behind them, and BA, W and BA chasing them using Zatana's Slow to secure the kill. Once you cap your Claymore, use the activate to easily take out high priority enemies in ganks. And remember if the enemy champion is playing is safe in the lane near where you are jungling, you can always tag team up with your fellow jungler and gank their lane. 

Teamfights: Take out their assassin. Just destroy them when they try to break through their frontline. So many assassins/low health bruisers do this constantly at the start of a team fight. Make them pay, and rethink their approach to team fights which will pay dividends late game. Also, it doesn't hurt to jump on Sinestro when he tries to E in. Next, focus the closest low health target. Your whole team should make this guy their next priority. You then move onto their next standing carry. Remember, your an assassin. Unleash your combos, and don't stand around trying to BA if you are drawing major attention. Ult when a champion is low for maximum effectiveness.

Mastering Q: If you play him a few times, you will start learning how to master your Q for both clearing and CC. You will even be able to connect on enemies who are constantly moving with enough practice.