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.
Pros / Cons
Decent survivabilty for a caster
High damage output endgame
Excellent survivability early game
You tend to get focused on
Smart enemies will stack MR
After the shield is gone you die fast
Insight to keep your damage up, clarity for the regen and the Force ones for higher damage out put endgame.
I start with a Doran's ring for the regen and ap which will keep you laning longer than the other team would like. It helps you keep your Q spammable.
I get the boots of Lucidity for the mantra cool down.
The Will of The ancients keeps you alive with it's twenty percent spell vamp and 80 AP doesn't hurt.
Rylai's for the bonus slow and ap.
Rabbadon's for the massive increase in AP.
Archangels for bonus mana and AP.
The game will probably be over before you can get this but if you can pick up a Hextech for the nice bonuses it gives you.
I build like this because her Q is easily her best skill. The shield gives you survivability and a nice nuke, and W is more helpful endgame than it is at the beginning because they are almost always hugging turrets. The shield's nuke may not be as powerful as walking the beam through enemies but it's range more than makes up for it.
I take ghost and Clarity so that I can run and survive.
Summoner spells are more personal preference than anything though.
Karma is a great team player. You can massively slow enemies with your Mantra Heavenly bond so running is out of the question.
You can even get hilarious and drop your Mantra'd shield on your tank and the laugh as the enemies attacks bounce off after taking a lot of damage.
If you see your allies are at low health drop a Mantra'd Q to heal up your allies and keep the fight going.