Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Just a short build i use that seems to be extremely effective as Kennen.
Runes: Now the runes, you don't need to use those. I don't even use those but i just put some i thought you might buy if you don't know what else to buy. You can also buy maybe health quints, for a little bit more survivability.
Summoner spells: You can also use ghost/smite, ghost/exhaust, ghost/teleport.
The reason i always use ghost is because in team fights i go down pretty quickly. especially since i have to be in the middle of things for my ulty. It helps me get away easily. Exhaust also helps get away, or helps get a kill, slows them down, or for 1v1 you can use exhaust and they wont be hitting really :p
Items: It's important you ALWAYS get a Zhonya's ring. The passive is great. adds 25% extra AP to your total AP. so like it says in the build, 503 AP, you'd really have almost 700. around 660 or so. Not quite sure. You can also go with Boots of swiftness but i like sorcerer's shoes because of the magic pen. it's great to have magic pen. You can substitute one of the items with Will of the Ancients, or any other item you's like, but i recommend those item's since they work extremely effectively for me.
Skill Sequence: lol i wasn't even sure what to put but what you want to do is get thundering shuriken, then electrical surge, then lightning rush, and then max lightning rush, electrical surge, and then lastly max out thundering shuriken.
Gameplay: In the beginning, since you will have boots, [NOTE: you can buy an Amplifying tome, and a health potion instead of boots for some nice AP, but i recommend boots with 3 pots, then an item that builds into Zhonya's, then sorcerer's shoes, mainly so that you have AP and you can kill] play defensively, and watch for who you're going against. Remember, 3 marks of the storm and the person is stunned.
While lane-ing, i reccomend that you try to get with someone that has some sort of disable [slow, stun, ect;] so that it's easier to get a kill.
Later in the game, you can get gold very fast. Lightning rush through a wave of minions and then use electrical surge to wipe them all out at once. It's a great way to farm some fast gold.
The beginning will be a little rough since your first item will be Zhonya's (first AP item). once you get it, you're on your way to domination. You should have somewhere between 140-200 AP once you get Zhonya's ring.
Team battles are important and it's essential you're there. After someone engages you can lightning rush and ulty and chase down people with it, then use electrical surge to mist likely finish them off, and if it doesn't kill them, they'll be stunned for sure so you can finish them off.
If you want you can engage too. Lightning rush into the team (make sure there together) and use ultimate and use the active on Zhonya's ring so that you don';t get hit, but they do. Then do as said up top ^^^
Good luck and have fun as Kennen. I hope this build worked as great for you as it did for me :)
In-game name: SCRAX