Kennen
the Heart of the Tempest
Kennen throws a fast moving shuriken towards a location, causing damage and adding a Mark of the Storm to any opponent that it hits.
Cooldown: 8/7/6/5/4
Range: 950
Kennen passively deals extra damage and adds a Mark of the Storm to his target every few attacks, and he can activate this ability to damage and add another Mark of the Storm to targets who are already marked.
Cooldown: 14/12/10/8/6
Range: 725
Kennen morphs into a lightning form, enabling him to pass through units and apply a Mark of the Storm. Kennen gains movement speed when entering this form, and attack speed when leaving it.
Cooldown: 10/9/8/7/6
Range: 200
Kennen summons a storm that strikes at nearby enemy champions for magical damage.
Cooldown: 120
Range: 550
You can stun your opponents by inflicting 3 Marks of the Storm upon them.
Lightning Rush can be used to initiate fights with its Energy return component, allowing him to use other abilities afterward.
You can land an initial Mark of the Storm debuff on an opponent with Thundering Shuriken, and then add to it with Electrical Surge.
Consider playing a bit more cautiously around Kennen when you have a Mark of the Storm debuff. If he hits you with 3 Marks of the Storm, you will get stunned.
Kennen is flimsy by nature - turn and attack him if he gets careless with Lightning Rush.