Kassadin

Ok.

Kassadin, once the best assasin in lol, is pretty shit right now.

Lets look at kassadin with full build. Say he has 650 AP and is level 18.

One rotation is about all the time he has to eliminate one target.

The damage dealt by one rotation of Kassadins skills is (With an 800 mana cost ulti) 170+455+140+325+180+455+360+390=2475 magic damage plus 125 physical for the auto on W and 410 true damage from ignite

factor in magic resist, for the sake of argument 35% reduction from a target who likely has MR from QSS, athenes, Abyssal, Aegis, etc.

2475x.65=1608 magic damage

If he has lich bane,

93.75+325=418.75 418.75x.65=272.1875

total 1880 magic damage, 62.5 physical (Kass wont be building armor pen, so this is very low), and 410 true.

Now, lets look at some other assassins

(Technically a mage, but more of an assassin mage)

~400 AP 220+320+250+340+60+80+425+320+100+40 (ludens)= 2155 magic damage (assuming annie takes one autoattack with molten shield on) plus 410 true damage from ignite

Apply the 35% reduction, and we get 1400.75 magic damage, plus 410 true.

Even with 250 more AP, and an item that grants a much higher AP ratio than ludens, a full build kassadin only outdamages a 3 item annie by 480, and only by 208 if he doesn't have lichbane. And this doesnt even include the persistant damage of tibbers (I am ignoring that because it would technically put Tibbers as the highest AP ratio in the game)

~300 AP 250+240+200+210+210+180+440+360(doubletap R)+52+150(lich bane)=2082 magic damage plus 410 from ignite apply the 35% reduction 1353 magic damage plus ignite Kass at full build with outdamage a 3 item Diana, though only barely if kass doesnt buy lich bane. The difference is that while kassadin has his ult at max charges, and will not be able to do a whole lot else until he gets his charges back, Diana can still proc her passive a few more times while she waits for cooldowns, while kassadin tickles the enemy with his Netherblade passive.

*numbers regarding how much AP these items would give and the reduction from armor and magic resist may be off, but you get the point.

Edit: I forgot to take Kassadins mana ratio into account. Too lazy to do more math though.