Not Updated For Current Season
Starts out as a hybrid spellcaster/tank.
Mid game you should be spellcaster/tank/physical damage.
Late game you are just a little improved.
Nasus drains his foe's spiritual energy, giving him a natural 10/15/20% lifesteal. The lifesteal value increments at levels 1, 6, and 11.
This is a decent passive providing some lifesteal. Lots of other guides might go "omgee lifesteal passive lets stack lifesteal it will be lolssss." And maybe that holds true 1 in 10 games. The other 9 games where the enemy has more than 2 stuns have fun being useless. Don't expect to rely on this for early game survivability. You wont be auto-attacking enough to get much return out of this, as you should only be last hitting with SS. Later on you will get pretty good HP return once you get your SS buffed and are thwocking with sheen procs. The passive synergizes well with his ultimate, allowing you to return more HP with your bonus damage. Not a whole lot else to say about his passive, as this build will not center on it, it is just a bonus.
Nasus's next attack will deal an additional 30/50/70/90/110 damage (+). Siphoning Strike permanently gains 2 damage whenever it kills an enemy.
Cooldown 9/8/7/6/5 seconds
Cost 20/25/30/35/40 Mana
Q - hence forth referred to as SS
this is your single target burst damage and the reason why 90% of guides are using it. You should focus on last hitting creeps with this in the laning phase especially, but you need to do so throughout the course of the game for maximum effectiveness. Siphon strike minion waves. Siphon strike neutral creeps. Siphon strike Heimer turrets, JitB, etc. By late game, if you have done a good job last hitting everything on the map, enjoy siphoning squishies for half HP with a sheen. An added bonus: siphon strike works on towers. Remember that you only need one level of this early to start building it up, as all levels add the same 2 bonus damage. Also, you can rapidly auto attack and then SS by hitting Q the moment you strike a creep with a normal attack. This makes last hitting easier and allows you put out damage quicker on champs and towers.
Nasus ages his target, slowing their movement and attack speed by 35% and reducing it further by 3/6/9/12/15% each second for 5 seconds.
Cooldown 15/15/15/15/15 seconds
Cost 100/100/100/100/100 Mana
W - hence forth referred to as, uh... wither
This is probably your most under-rated ability. It is simply one of the best snares/slows in the game because of its 5-second duration and the fact that it both decreases movement speed and attack speed, rendering a DPS carry essentially useless in a team battle for several seconds. It causes no damage but with the new system it will net you an assist if you slow an enemy for an ally to pick off. It has a relatively high mana cost, so in the laning phase try to use it sparingly and only when you think it will result in a kill/assist or at least result in some good damage, and for the love of god don not waste 100 mana casting it on someone as a harassment if you aren'tt going to attack. Good for escaping, ganking, chasing, and team battles. In a team battle use it right away on the enemy DPS carry. This spell does not draw tower agro, which can be convenient. Sadly, this spell is raped by mercury treads. If possible use it on champs without merc treads, cleanse, quicksilver, etc.
After a brief delay, the target area becomes desecrated. Enemies in the area have their armor reduced by 20/25/30/35/40 and are dealt 20/34/48/62/76 (+0.2) magic damage each second.
Cooldown 12/12/12/12/12 seconds
Cost 70/85/100/115/130 Mana
E - hence forth referred to as SF
This is a great skill during all phases of the game, be it laning, jungling, pushing, or team battles. In fact, this skill has so many uses that I can't cover them all here. It will take some good playtime to discover them all. It is an especially great tool for farming, harassing, and zone control early on. You don't want to level it too quickly or too slowly, because early game you don't want SF killing off an entire creep wave, just taking it down enough so that you can last hit with SS. By lvl 11, however, or whenever team fights become frequent, you want to have it maxed for the most usefulness. In the laning phase try to maximize its effectiveness by placing it so that the AOE will hit the largest amount of creeps as well as harass the enemy. If you drop it when an enemy is running up to last hit a creep it will force them to either retreat and not get the last hit gold, or commit but take some damage. In a team battle drop it in the middle of the action, its armor reduction will make your entire teams attacks that much more effective. When defending pushes, simply dropping it in front of a tower can often keep enemies at bay. Keep in mind this spell will draw tower aggro.
Fury of the Sands
Nasus becomes empowered in the sandstorm, gaining 300/450/600 health. While the storm rages, he drains 3/4/5 (+0.01)% of nearby enemies' health each second (240 damage max per second) and converts it into bonus attack damage.
Cooldown 120/120/120 seconds
Cost 150/150/150 Mana
R - You're the man now, dawg.
What an ultimate. You go from sweet to sweeter instantly. This spell will turn you into a force to be reckoned with, and is the reason a good Nasus is built for durability rather than DPS. Some of the other guides might say "omg pop ult and you can 1v1 anyone its so sweet!!". Congratulations on your 1 kill, I know your K/D is probably more important to you than the impending team battle and subsequent rapage of your entire middle lane because you are nigh useless now. In his ultimate form Nasus can really punish an enemy team, and that is what it should be used for. If nothing else, it will wreak havoc, causing the enemy to scatter and allowing your DPS to make quick work of a cluster****. Hopefully your team has some CC and you can enjoy melting the enemy teams faces off like Raiders of the Lost Ark. It will take some practice to learn when to pop this for maximum effectiveness.