Kassadin

Try that Again

Lane harassment and consistent damage output.

Improved attacks and sustained damage

Fleet Footwork

Attacking and moving builds Energy stacks. At 100 stacks, your next attack heals you and grants increased MS.
Triumph

Takedowns restore 5% of your missing health and grant an additional 20 gold.
Legend: Haste

Takedowns on enemies grant permanent Basic Ability Haste.
Coup de Grace

Deal more damage to low health enemy champions.

Burst damage and target access

Taste of Blood

Heal when you damage an enemy champion.
Treasure Hunter

Unique takedowns grant additional gold the first time they are collected.

Fleet Footwork is excellent for lane phase health sustain as well as massive late-game teamfight healing.

Triumph's mid-fight burst heal allows you to pop off in teamfights with mulitple kills with [R].

As a melee mage Tenacity goes a long way in providing you safety from early ganks before 6.

Coup De Grace's execution damage synergizes well with your heavy scaling and reset based teamfighting.

Taste of Blood further improves your lane phase health sustain for early trading.

Ravenous Hunter will grant you a ton of teamfight health sustian so that you are able to get multiple casts of you [R] off without being killed.