Have you seen many Nasus players out there? Certainly not as many as the vast ammount of annoying Tryndameres and Master Yis who walk up and 3 hit you 30 minutes in. Nasus is in fact very underplayed for how overpowered he is. I hope by looking through this guide, it will inspire many new Nasus fans.

Some will disagree but I believe having the following runes is the best for Nasus:
Greater Mark of Desolation - 15 armor penetration (9 runes)
- 13 armor (9 runes)
- 13 magic resist (9 runes)
Greater Quintessence of Desolation - 10 armor penetration (3 runes)

Lets take a look at the armor penetration. Often forgotten on the battlefield, armor penetration plays a huge role in, well... killing people!! And with 25 armor on the enemy champion that means nothing to you, that helps.
Next, the armor and magic resist. You will definitely need these in early game for defence against the harass of the ranged carries TRYING to prevent you from farming your Q ability . This ability will be talked about in detail later.

Nasus runs a standard 9/21/0 mastery to maximize his defensive strengths. The 9 in offense is to obtain that 10% armor penetration that will go along nice with the armor penetration runes. The defensive tree however raises some questions that will be answered later. But obviously the last mastery in defense saving you from disables and increasing your health is a winner.

The Doran's Sheild is one of my favourite starting items, and I often take it on many champions. This is because of the 3 things it gives you. You will recieve an extra 8 health per 5 seconds, 120 bonus health, and 10 armor. What more could you ask for at level 1?
This item is for early game and will ensure you are not mana starved. You will be able to farm Siphoning Strike, and Wither as needed.
CORE ITEM BUILD

Trinity Force is the most expensive item in the game for a reason. It is amazing! You get the attack speed, movement speed, and crit chance of the Zeal , you get the health, attack damage, and chance of slow on hit of the Phage , and you also get the mana, and raw power of the Sheen's passive and some useless AP you wont ever need on Nasus. (Yes I am to Trinity Force as 13 year old girls are to Twilight)
Warmogs is Warmogs. Love it or don't admit you hate it. 1370 Health and 45 Health regen per 5 when maxed, how can you hate it?? I WILL TROLL YOU IF YOU HATE IT <3
Atma's Impaler is great when you have a Warmogs (often refered to as Atmogs when in the same build). Based on the health by the time level 18 is hit, you will get aprox. 66 AD in this build, and the fixed 18% crit and 45 armor.

SITUATIONAL ITEMS
OR
Both of these items are great but Mercury's Treads should be taken almost every game. The reason being that Ninja Tabi only provide 12% dodge and 25 armor (which is nice) but the Treads give you the Tenacity you will most likely need.
By all means if they have a Tryndamere and a Vayne go for the Ninja Tabi but only when hard AD carries are threats to your survival.

OR
The Force of Nature is great but serves a lesser purpose if the enemy team doesnt have a lot of AP. Even so, rediculous health regeneration, and some movement speed is great. If the situation shows heavy AD on the enemy team, a Thornmail would be a better choice.
A little about the Thornmail: 1) People will either avoid you or kill themselves attacking you. 2) 100 armor?!?!
3) It will make the AD carry rage :)

OR OR

Now, I understand why a lot of you are not a fan of the Guardian Angel. It seems like a troll item by giving you a second life. But get past that and notice the 68 armor and 38 magic resist. It does not seem like much, but it really does help.
MMM the Sunfire Cape. A lovely item that would help your Atma's Impaler slightly, and also grant you 45 armor. But wait theres more... 35 magic damage gets inflicted to nearby enemies while they are simply standing near you! So in a team fight that lasts 30 seconds, lets assume you live until the end (You probably will), and you are touching 2 enemies per second on average (most likely more), this means that you have inflicted 2100 damage by simply standing near people. Can you say OVERPOWERED?
And for the Banshee's Veil. 375 health and mana, with 50 magic resist. Another passive! :D every 45 seconds you block one negative spell the enemy throws at you. This is good on its own, but think of how it psychologically affects people. :"I'm not going to fling him because it won't do anything" :"I won't bother snaring him because it won't work" See what i'm getting at? This item has a second passive: "I won't bother hitting the dude with the Banshee's."

I feel that this is a pretty standard skill sequence for Nasus. The Q first so you may start farming right away, followed by the Wither to either set up a gank or chase. Maxing the Siphoning Strike first is sometimes thought of as being an unskilled Nasus, but think about it. Faster farm and more damage, just do it.
Spirit fire is not my favourite skill, but it gets small jobs done like pushing minions and oddly enough, scaring people away.
This is known to every non-Nasus player as: "Oh noes he's in god mode, run! I know theres 3 of us but run!" And honestly, with Nasus's passive, Soul Eater , Siphoning Strike, and the passive AoE damage from Fury of the Sands, Nasus can 3v1 against weaker champions.

Lets talk about the skills a little bit now.
This is the bane of Nasus's existence, the skill that enrages enemies, and the skill that needs much farming. Every time Nasus kills anything with Siphoning Strike, he gains 3 bonus damage for the next use. you need to be on top of your farming game in order to hurt with this skill. It has a short cooldown (8/7/6/5/4 seconds) which leaves you wanting more damage to hurt the enemy team. On average, you should be aiming for 450 bonus damage on this skill minimum, however there is no cap, go nuts! This means you need to Siphon 150 minions minimum. It sounds easy but you need timing (you will be suprised how many times you leave a minion with 1-20 hp). Late game, this skill will secure you many kills.
Every Summoner is familiar with the spell Exhaust , How about having one on a 15/14/13/12/11 second cooldown? Sounds awesome! This makes Nasus a pain in the butt to fight because not only does it reduce movement speed, but it also reduces attack speed at the same rate (35+12/24/36/48/60%) Yes, what I am saying is it reduces the target enemy's attack and movement speed by 95% at level 5 (not initially, starts minimal, but increases per second for 5 seconds to 95%). Who do you hit with this? You guessed it! The AD carry, they will not be able to kill anything.
Again, not my favourite skill, but serves minor purposes. When you need to go back to the base while in laning phase, drop this down on the enemy minion wave to keep them from pushing your tower. Other than that, it is not a huge source of damage until level 5 when you deal 215 magic damage on cast, and 43 damage per second to champions standing in the radius. DO NOT use this to harass, you will be mana starved and not be able to farm Siphoning Strike efficiently in early game.
How much do you like massive AoE? You better be a fan because Nasus can take down 3/4/5% of multiple enemies health per second by using this skill, and also gain 300/450/600 health on cast. This is perhaps one of the most over powered ultimates in the game, and when used wisely can strike fear into the souls of your enemies. I prefer to use it after the re-birth from Guardian Angel for a suprise nuke from hell, but the choice is yours :).

MAIN SUMMONER SPELLS
Ghost: Ghost is a great spell to have that is very multi purpose. It can be used to chase a wounded enemy, run from a gank, save a team mate, the list goes on. Ghost should almost always be taken with Nasus because it ensures more survivability, and power to control your lane.

Teleport: Not going to lie, this is my favourite summoner spell. Also being multi purpose, teleport is under used and often replaced with an ignite -.-" Teleport can be used to gank, to farm an incoming minion wave, and to push a lane. What Teleport is not used for is to get back into your lane in early game. Just don't do it.

OTHER VIABLE SUBSTITUTES
Flash can be a good substitute for Ghost, but in the end does not get you as far as ghost will. Flash is often taken by squishy champions for a quick and immediate get-away, but Nasus is tanky enough to endure some damage while running.

Cleanse is another viable spell to have to break out of crowd control and continue laying waste to enemies.

Ignite is my least favourite spell but I can admit that it secures kills from time to time and can counter a few champions like and . If you prefer ignite, go for it.

Personally, I would not take Promote over Ghost or Teleport, but if your heart desires, go for it.

WHAT SHOULD NOT BE TAKEN AND WHY

I understand the obsession of having 2 target slows, but you do not need it. Wither is plenty efficient.

You have a lifesteal passive, use it.

Your team will troll you, and Nasus has a hard time dying as it is, don't base your game around the assumption that you will die.

Jungle Nasus is possible, I have done it. So you don't have to! Why? The ammount of farm you will get for Siphoning Strike will be low, and you have to recall frequently. Don't do it.

Grab your Chalice of Harmony, and you are good to go.

Leave it to the supports.

Nasus in Dominion?

Pros:
1)Strong, Tanky DPS.
2)Great sustain in lane
3)Can counter many team compositions
4)Crazy consistant damage
5) Awesome survivability

Cons:
1)Underpowered if underfarmed
2)Constant need to farm minions
3)Often targetted
4)Easy to kite

When playing Nasus, I usually take the liberty of shutting down the enemy carry (AD before AP). The reason for this is because Nasus is so good at it! Wither gives you time to land 2 Siphons on a champion. That being said, Wither the carry, and go to town! Siphoning Strike often 2 or 3 hits squishies and even if you do not kill them, they are eliminated from the fight.

Initiating: Nasus is always one of the most tanky on your team, so you will be doing the initiating. It is the best idea to open with Wither and rush the carry to Siphon. As a result, you will often be focused, but with crowd conrtol is no longer a problem.

If you have a lane partner, Nasus can play a minor support role in helping team mates. Obviously when your partner is being chased, Wither the enemy champion and engage. Why engage? They have no movement or attack speed!

When with your entire team, stand in the front and absorb that incoming damage for your team (because you can afford to be hit a few times). Engage with Wither and Siphoning Strike those Squishies!

THE MOST IMPORTANT ASPECT. If your farming game is weak, do not expect to do well with Nasus. You will get many assists but will not plow through teams and get triple kills. When in laning stage, only last hit. You should never auto attack unless you need health back from your passive . Doing this will ensure you plenty of bonus damage from Siphoning Strike and a faceroll champion late game.

When playing against Akali, remember she has crazy BURST damage. She will hit you hard once every few seconds. Knowing this, you MUST stay with her and put Nasus's constant damage from Siphoning Strike to use.
Jax unlike Akali has better consistant damage, with a high dodge chance. When going toe to toe with him until one of you dies, it will be you. Knowing this, open with then back up and use do not auto attack Jax! this is because once he dodges your attack, he can stun you with then his ulti gets stacked then your dead. After using Wither wait until Siphoning Strike comes off cooldown and hit him again, back up and repeat.

THESE CHAMPIONS WILL GIVE YOU TROUBLE
Vayne's skill will rip you apart in late game. You NEED to stay close to her. is needed to kill her because she can take anything down in seconds. She should always be your target for this, and your main objective to take down.
Kog is another champion you need to shut down. With his , and a , any target is easy to take down. Both of these champions are very squishy and can be dropped in a few hits. Just do it.

TANKY PROBLEMS
Again, with , and some tanky items, Warwick poses as a threat because he also has a healing passive .
Udyr is yet another Bloodrazor champion, usually tanky can cause you problems. Try to have a team mate with a stun/snare with you before engaging these champions.

YOUR PREY
All three of these champions will not hurt you mid-late game and should be focused and killed within seconds. a Siphoning Strike and a few auto attacks should do it.

A FIGHT BETWEEN BROTHERS
vs Personally, my favourite match-up of champions. Renekton vs. Nasus. Neither of them have a solid advantage over the other, they are both great tanky DPS champions, but usually the more fed one wins. If you think you have an edge on Renekton, by all means take him down. But a fed Renekton is pretty scary. The choice is yours.

First of all, make sure you take your tower before making it your mission to take the mid tower. Winning your lane is important in LoL. What makes Nasus a great pusher, is his . YES! You can Siphon towers! Once you get your sheen, you can drop towers from full to nothing in seconds! Use this advantage along with to surprise push a tower as well. If you take 3 or 4 towers in a game, your team will love you and you will most likely win.
Taking towers wins games. Nasus is one of (if not) the best at tower killing.

Here it is, the FaQ. Here are some of the questions that may come up in the average player.
1)Why all the armor penetration runes, why not damage? The first few months of playing LoL I thought the same thing, why not flat damage? Armor penetration is highly under rated by many Summoners but it is a great asset to Nasus. With this build, plenty of AD is established with and , no more is needed. Also, it avoids having to buy a or a . Next, many squishy enemies will not invest into armor, which makes them seem like they in fact have none. But even if they do, You have penetration(mainly for )

2)Why not take utility in masteries? The only useful utility I can see for Nasus is mana regen and total mana. This is not worth giving up the 21 in Defence for Juggernaut and the 9 in offence for the armor penetration. Also, mana regen would only be useful in early game which is why you temporarily buy a . Experience and gold utilities are not needed because you will have to be farming through mid game and into late game. You will have enough gold/experience.

3)Why not take movement speed in masteries? gives you 12% move speed, and gives you even more (if you decide to get it).

4)Are other roles for Nasus viable (ex. full DPS or full tank)? Yes in fact full tank Nasus is a great way to play him, but personally i like having the extra killing power. And for full DPS Nasus grabbing a and just seems impractical. Leave that to your AD carry.

5)Why Atma's Impaler and Warmogs (Atmogs)? This is purely a personal preference. Many of you readers will not like Atma's on Nasus and thats fine. A substitute would be a and something else which is great as well.

6)Why and not with a potion? With your armor runes, and the Dorans, you will have a bonus 23 armor, which is plenty for early game. This way you can afford to be harassed a little with minimal effect. Also, 120 bonus health is very nice. And lastly, you have a lifesteal passive, you dont need a potion, attack the creep wave in your tower.

7)Would some AP benefit? Don't bother with AP on Nasus. does not scale well with AP and you will only get an extra couple percent out of

Thanks for reading guys! I had a lot of fun with this. If you try this build, Let me know how your game went, even post a screen shot of your results! I really do care about getting involved in the LoL community, and I would like to share what knowledge I have with you guys.

Any constructive criticism is accepted in open arms, so feel free to comment on anything you find needs work, I appreciate it!