Originally Posted by dovvntempo
some of the other funkier items include deathfire grasp and haunting guise, and I have yet to really put them to the test. I'll have to try them all though.
Haunting Guise is pretty good. It's cheap, and provides CD reduction and magic penetration. The health and mana regen are just gravy.
I usually get it after Rod of Ages and Boots of Mobility. After that, my item build really depends on the other team. Frozen Heart is a great item if they're DPS heavy- mana for you for riftwalking and less damage for them. With Frozen Heart (25%), Haunting Guise (10%), and masteries (9%), you should be at the CD reduc cap too.
If either team is magic heavy, I tend to go for an Abyssal Scepter. I know Void Staff may seem more useful, because it gives you mana, AP, and magic penetration. However, only magic resist reduction (like Abyssal and Fiddle's passive) can make an opponent have negative magic resist and Abyssal's aura helps out your team mates. Between Haunting Guise (20), runes (9-ish), and the magic pen mastery (15%), you should be all set for magic penetration. If you're getting pummeled by enemy casters, additional magic resist is more useful than 250 mana because Kassadin's natural resists are pretty ****.
So my item build looks like this:
1) Sapphire Crystal and 2 Health Pots or 1 Mana/1 Health
3) Boots of Speed
4) Rod of Ages (the earlier you get it, the better)
5) Boots of Mobility (great for kiting, running away, chasing, and
6) Haunting Guise
7) Abyssal Scepter/Frozen Heart
9) MOAR mana/AP/survivability, but the game should be over by now
I'm not a huge fan of Mejai's because I can't count on it. Yeah, it's cheap AP, but if your team is doing badly, you won't have many stacks. In mid-ELO, your teammates' skill can be a bit of a ****shoot. Additionally, all Mejai's does is AP. Most of the items that I get on Kassadin serve multiple purposes- RoA gives Kassadin everything he needs, Haunting Guise has CD reduc and magic pen, Frozen Heart and Abyssal make you both tougher and more lethal, etc.
However, I'm going to try it later today and see how it goes, because I see a lot of caster champs getting it.
Someone earlier asked about runes and no one has really addressed those, so I'll give it a stab. I have a generic rune page for casters, but it works decently on Kassadin.
Reds-> Magic Penetration
Blues-> MP regen/level (they're cheaper and help mid- and end-game when Kass really needs it)*
As dovvtempo said, there are a lot of different builds that can work on Kassadin. It all depends on your playstyle. Hope this helps!