Karthus Build Guide by SWAGRID

Since I haven't seen it in your guide (might have overlooked it), Why do you choose Nashor's Tooth over Morello's Evil Tome? With either Blue Buff or Elixir you would also get to the CDR cap, and you would only have 5% CDR less if you haven't. Great guide overall, and I'm not saying that Nashor's Tooth isn't a great option, I'm just wondering why you chose Nashor's over Morello's.

this is the worst troll karthus guide ive ever seen

+, works great.

Worked like a bauss. 10 / 0 / 0 in first gime

1+!

ok I tried this build and, how i espect, it's the worst build i've ever seen:
first of all, Karthus really doesn't need CDR, because his Q is already really quickly (1 sec of cdr...) and the 0,4 sec saved is really tiny and useless bonus because the ability Q has 0,5 delay explosion.
you have also chosen a bad items for your purpose:
-Nashor is really useless, it's much better the morello tome for these reasons:
1)nashor gives you 65 ap (really poor bonus) and 25% cdr; morello gives you 20% cdr (a really tiny difference and after i show u how have 40% cdr with better items), 75 AP (better than nashor) and mana regen better than nashor, and also morello is less expensive! (only 2330, and in the build you can have kage pick.. 5 gold per sec.. good). the attack speed bonus is REALLY useless on karthus because, if you play it good, you don't autoattack but you always spam Q... Q, Q and again Q! always! you can not physically use auto attack with karthus! that also why you must buy in early the tears of the goddess and upgrade after in archangel staff: with the karthus's Q-spam you can complete the 1000 mana bonus really quickly and you will don't have mana problems in mid and late game
2) the gunblade is really a waste of money, really... you only need WotA.. with 3100 (500 less gunblade) you can buy Zhonya's Hourglass that gives you 100 AP (weeery good), 50 armor and a very active ability for karthus: immortality for 2 second, 2 second of more damage for you (thanks E aura, when zhonya is active the aura remain!)
now Try this build: Sorcerer boots, Rod of Ages, WotA, Rabadon, archangel staff, zhonya hourglass or void staff (depends if enemy has a lot of magic resist)
If you really want cdr 40%, replace archangel staff with morello and take blue buff .... easy....
or you can also use 9/0/21 masteries (that gives you 10% cdr) and buy blue potion: 20(morello9+10(masteries)+10(blue pot)=40%
but, as already I say, cdr for karthus isn't really important... he has already little cooldowns... is much better build AP for tons of damage

Swagrid only one question.. Isn´t a better idea just getting CDR Boots (15%) and instead of Nashors tooth (The one you buy only bacause of CDR and a bit of AP) getting Maybe Zhonyas/deathgrasp to increase AP a bit more (or having a nice extra spell with deathgrasp) you would be only losing like 10secs. in ult. and... maybe 1sec. in Wall ? So... Do you think may be worh it??

Several things wrong with this build

1. Nashors tooth - while you can argue for the merits of this item, that being HUGE cdr with good mana regen, attack speed and ap nearly a third of the items cost is wasted in attack speed and as such morelos evil tomb would fill this spot with more ap and mana regen with nearly as much cdr and a useful active based on the fact that you don't have ignite

2. Hexetec Gunblade - Now the problems with this item fall much like with nashors, while it does give some good stats and a good active, you waste more than half your gold this time around on AD and life steal you will barely ever use as because you are running a CDR centric build you will never use. This item can be replaced with a rylais crystal scepter which will give you survivability, more so than the gunblade spell vamp will grant because of the slow that lets your will of the ancient soak up HP off of your defile, the slow which as I said synergizes with WotA and more AP which again synergizes with WotA

3. Clarity - You honestly don't need this spell, no one does. Especially when you build rod of ages with smart use of defile turning it off whenever nothing important is present to kill in the active and using it to last hit you will never run out of mana and something like running revive in conjunction with teleport would be more appropriate for your build

i only rated down because it doesnt work for me. i do find it working better if i get will of ancients much later, and focus on getting deathcap before it. tried about 5 times each way, my adjustment at least works better for me