At level 1, we start with the E on Kassadin. Alternatively, you could start with the Q to get a slightly better trade, but I don’t think that’s necessary. Kassadin can’t get much out of a good trade until level 6, and it’s more important to secure as many minions as possible. The E is much more useful for this, as you can, for example, lasthit the three melee minions at the same time in the first wave.

At level 2, we skill the W to make it easier to lascade, as we are often pushed under the tower. We select the Q at level 3, and from then on we maximize the E. It is the most important ability for your waveclear and also the one you can use most often in fights. The cooldown is reduced as soon as abilities are used in your vicinity, whether by enemies or allies. The slowdown also increases with each point.

After E, I recommend investing three points in Q before maximizing W. By level 16, the W should be fully developed, as each point increases the mana returned. This is particularly important as you can use your mana optimally for several Ults as the cooldown reduction increases in the lategame. The Q is a bit more useful earlier in the game, which is why I would still put the points in here until you reach level 10 :D.

Kassadin is not a mechanically demanding champion and doesn’t have any complicated combos that you absolutely have to master. Concentrate on getting as many Ults and W-ins on your opponents as possible, as this will make up the majority of your damage. You also regenerate your mana through the W, which allows you to use more Ults in longer fights.

A useful mechanic is the “flashing” of your ult: You can flash in during the ult animation, similar to what Cassiopeia does with her ult, to surprise your opponents. This extends the range of your ult. The sequence would then be: Ult -> Flash – and then the remaining abilities

A simple, effective combo could look like this: Ult -> W -> Q -> E -> Ult. You can place an autoattack in front of your W for the autoattack reset, but the longer the game goes on, the less time you have for this and the better it is to simply use the W directly.