Frost Magic and You: Short Guide to Kel'thuzad

Kel'thuzad is a a lategame hero with strong crowd control options who excels at destroying clumped up enemies and getting them stuck in groups through the combination of his abilities. He trades weak early game damage for some of the highest nuke and crowd control potential later on in the game.

Early on your focus should be on using  Frost Nova  and  Chains of Kel'Thuzad  to quickly stack up your  Master of the Cold Dark  progress, don't risk your life for it though. Damage in early game isn't your concern - utilise your crowd control instead. Many people take  Barbed Chains  instead of  Blighted Frost  but I don't agree with it - I find Kel'thuzad's damage to be high as it is and more CC is always good.

You also want to focus on getting your  Phylactery of Kel'Thuzad  filled as quickly as possible. Having a second life is absolutely crucial later on as it lets you keep an advantage in teamfights by remaining alive despite being taken down. The extra spell vamp also increases your survivability. I would sometimes take  Armor of the Archlich  against an autoattack-heavy team and  Strip Shields  vs someone like Fenix but in general I don't grab them - the power behind an extra life is too high.

Your goal is to reach 30 stacks as early as possible so that your damage can skyrocket. The earlier it happens, the happier your team is. Ideally you want to do it before you reach level 10 so that your  Shadow Fissure  can obliterate enemies along with the rest of your combo. This is further empowered by  Chilling Touch  which receives the boost from  Master of the Cold Dark  once you finish it. Why touch over  [Glacial Spike]*  ? It's simple - While the spike increases your threat range, it greatly weakens your damage and threat within your default cast range. I see it as a support wheels talent for those new to Kel'thuzad and/or those not too familiar with his potential. It also makes you completely ineffective against Genji and Tracer while touch allows you to put up some resistance against an otherwise unwinnable match-up. If you're ever against these two, consider taking  Frost Blast  over Fissure to paralyse them in fights / force an unfavourable Recall. You're always going to be weak against these two, but this lets you punish them for diving you in a fight.

At level 13 you should take  Chains of Ice  to make your chains even deadlier than usual with the potent slow to prevent enemies from leaving your combo. There really isn't a choice on this tier.

Level 16 presents you with  Hungering Cold  which empowers middle nova blasts. While a lot of people take Power of Icecrown thanks to its ease of use and long duration, Hungering Cold essentially doubles the damage of your  Death and Decay  and procs on the middle nova explosion. It also works with your chains, your basic attacks and any other source of damage you can bring to the fight. The amount of extra damage gained this way can be equal to an extra  Shadow Fissure  in terms of numbers.

For level 20 my personal favourite is  Shifting Malice  as it gives you a slight dose of mobility, deals respectable damage (450+ at 20) and resets on any takedown you get to participate in or are near of. The Damned Return is worth considering sometimes, but the static nature of the ability makes me not take it.  Deathchill  can be a potent option if your team has someone who heavily benefits from slows and can abuse them such as Fenix or Greymane via Executioner.