's ult is a short ranged stun, most assassins can just blink toward their target and then burst them down before they have time to react. How should Cassiopeia deal with this? When they blink toward her, they completely avoid the ult.
umbraˉ3 votesYou don't, you just sit there and take it.
heckin dead1 voteswait to ult until after they blink.
Handy Sandy 2 voteswait to ult until after they blink.
But then I'm dead before I can cast it.
legionnaire991 votesBut then I'm dead before I can cast it.
or your w
Ruin Lance1 votesyou know there is a subreddit for this? you're a lot more likely to find a cassiopeia main there than here.
Succubús GF1 votesIf it's assassins like 
you put your w over them and as soon as they walk to get out of it, usually they will walk forward to counter attack, use your ult and delete them
Quepha1 votesStand as far away from them as possible, they are your natural predator. If you can catch them unawares, then lock them down with W and get a damage lead. When they jump on you, your best bet is to buy some time with Seraph's and/or Zhonya's for your team to peel/heal/shield you.
EndlessSorcerer1 votes
+ Health
Handy Sandy 2 votes
Had over 3k and banshee's veil
Penta Ace1 votesIts mostly about knowing the patterns of the the assasin. For example, If you know where zed will land after he ults, you can catch him pretty easily. Your W is also probably your best chance to stun an assasin if they are in it since they cannot blink or flash while in it. Timing the W and aiming at just the right distance is key. Lastly having a crystal scepter works well since it helps against mobility assasins and you can practically perma-slow with ur low cd abilities.