The strength of Kennen with a shadow Morellonomicon (More-evil-lonomicon), in a Hellion comp (thus my name, Hellnomicon), cannot be understated.
It is ridiculously spammable, it is easy to force, and it is ridiculously broken. Because More-evil-lonomicon applies a 100% max HP burn to all hit by the caster's spell, Kennen applies damage to basically the entire field fairly reliably (and his stun only makes this stronger), and the comp allows you to have the sustain to wait it out and have the burn do its work, by and large.
I'm pretty sure I've discovered something Riot is going to nerf fast. Justifiably so. But hey, until they do...freelo is mine, I am legit able to climb ridiculously easily with it.