Let's analyse Nunu...

Strengths: Has a lot of health, decent damage output early game, DPS's best friend (apart from maybe Morgana), great chaser, one of the strongest nukes in the game, can lane effectively, can jungle very quickly and gank effectively, can counter jungle effectively.

Weaknesses: Damage output late game not great unless you get a perfect ult, but this can be incredibly difficult to pull off

Nunu is rated as one of the easiest champions to play, and in many ways they're right. You just run up to people, throw an iceball run away or chase them down, you don't use your skills in a precise order. However, some experience is required, and great timing. His build is highly situational but I would recomend a build with lots of health and a fair amount of AP. Tank sort of works, but his survivability doesn't go up as much as his damage goes up from health. His ult has a 2.5 ratio (I believe this is highest in the game).

Nunu always takes flash as an escape mechanism because combined with bloodboil he is very hard to kill unless you have been seriously overextended in enemy territory alone and all 5 of them chase you and even then they will require some serious CC.

My skill order for Nunu is for jungling, and for laning it is different so make sure to look up the section on that too.

For jungling you want smite and flash.

Items: Doran's shield, 1 health pot
Skills: Q, E, Q, W. (consume, Iceball, consume, blood boil)[/u]

Full credits to stonewall for this build and route, I would search for his video on youtube to see exactly what he does but the fastest jungling route is big wolf, and just the big one of the three (because you can kill it before bluebuff spawns), followed by blue buff, followed by the wolves, wraiths, and lizard then golems. However, I would perhaps recommend taking golems first in order to keep redbuff for longer because you definitely wanna gank after this.

Hopefully the other team will be overextended in which case you run diagonally towards them cutting off their path in the bush because Nunu cannot slow what Nunu cannot see. Hopefully your lane mate at this point will be smart enough to be running towards you. You should blood boil them. If they are not overextended there's still a chance you can get them but it will not be as simple as this. Consider how much burst your allies can put out.

If they have an enemy jungler consider where he is likely to start. If it is bluebuff, you may decide to counter jungle. You should only do this however if their team are laned and you know they HAVE to start there. Go to their golems. Consume and smite one. Go to their wraiths, consume the big one and smite a small one. Return to your jungle, health pot and take blue buff and continue as normal and aim to gank first. If the enemy jungler is holding a lane because your team have pushed the champs consider taking one of their buffs if they have not already done so. It is the counter jungling that Nunu can do so quickly that sets him aside from other junglers. You then want to ward dragon. Nunu is perhaps the best dragon stealer of all the junglers. With consume doing crazy minion true damage, and smite in combination he can steal it very easily. Make sure it is warded, flash through a wall at the right time and do it or even just run straight in. Level 5 consume with smite

Word of warning: Nunu does not want to get in a head on fight 1vs1 with either Udyr or Wwarwick unless they are on low health and he is not, and with WW even then you want to be careful.

Another great thing about jungle Nunu is he can hold mid very well for the solo mid to gank. Even against a solid mid mage or dps by combining iceball harrass with consume and passive procs, he can hold the lane for a very long time and even expect to leave the lane with full health and the enemy at half health depending on who they are. A kill would be very unlikely unless they were quite stupid though.

For laning I'd recommend clarity and flash
Start with a mana crystal and rush boots and catalyst.

Clarity combined with the passive means excellent harrass and with the mastery in it your lane mate will have it as well. If for every two iceballs combined with one consume you can take off a larger percentage of their health than they can then spam them like mad. If possible, to lane controll let your partner get bush controll and put yourself at the minions. They won't be able to farm because you'll Ice them, your partner will be able to harrass in the bush, and you can proc your passive as much as you like. You should auto attack sparingly though, and still maintain last hits.

If your jungler is coming to gank, make sure when he goes for them you will be able to blood boil him and try to be able to slow them. Slow down the squishier target and fingers crossed you'll have a kill.

1. Item build:
Your first return to base if you think you'd be better to return for health should include boots to gank and a health or mana crystal if possible. You want to rush catalyst and 9/10 times go for Rod of Ages (RoA) before Banshee's Veil. Then usually an abysal sceptre

Nunu is not as dependent on Banshee's veil as you might think. If the enemy team only has one cancelling disable, the chance that they will have saved it for you is slim so you won't need it. If they have a ridiculous amount, Banshee's just won't help that much and you will probably end up trying to just wait for them to engage your other team mates before you slowly wriggle yourself into the right position. Moreover, Banshee's is likely to be taken off by a non-CC non-ult-cancelling-spell. My favourite item build is rod of ages, merc treads, banshee's, abysal sceptre.

After that I would probably recommend a Zhonya's hour glass (active does cancel ult) or a Rabadon's deathcap or even both if you just want to do some ridiuclous ults. If you are at the point where you can troll it is very fun to use Guinsoo's. Your auto attack plus slow from ice balls with blood boil on keeps it at full stacks and you hit them surprisingly fast. Very fun to chase and kill people with it :D.

You want health, AP, and magic resist. DPS's are not so much of a threat to Nunu as he can ice ball them (slowing their attack speed as well as movement speed) and just step out of range if they are too much of a problem. If there is a particularly annoying dps though take thornmail as your magic penetration and super health will ruin them.


2. How to team fight
- Blood boil your dps, immediately, even if they are not in range. They need to be as manouverable as possible to position themselves for the killing blows. Once you have a RoA or banshee's you shouldn't run out of mana so don't be afraid to spam it.
- Ice ball their squishies prioritizing DPS. You reduce attack speed and obviously want to take them out first so the slow will make it easier for you team to focus them, in theory.
- Consume: Whenver it is up consume a minion if close by. With AP you significantly increase your health and will stay to put out more damage.
-Ulti: wait for their CC to be used. position yourself on top of the squishiest character that puts you at the centre of their team. Don't be greedy. It is better to do 60% damage to the three squishiest champs if you cancel early than it is to get only 100% on the tank. Although, if it guarantees a kill on just one squishy you might choose to do that. In short judge the cancellation well.

3. The use of blood boil
This may feel like Nunu's most boring skill, but actually it makes him an amazing support and a lot of people underuse it. You can actually blood boil anything targettable on your team. That includes minions, heimerdinger towers and even (rather uselessly) Teemo mushrooms. If you are pushing a tower alone, make sure you blood boil that big tanky minion. When you have enough mana you always want to use it on an ally champion even just to get around the map fast. The cooldown on it with no CDR items means it the effect runs out as the cooldown turns off. Please, if you have the mana, spam this skill!

Finally when Chasing, you don't always want to blood boil the DPS. It may be more beneficial to blood boil the guy ahead of you all if they have some CC that will help you catch up to them.