Hello this is my second build I hope you enjoy and hope it gets you as many kills as I did and have as much fun as i have as Karthus. Karthus is a lot of fun and a lot of people forget about his ult and stay in lane at low health and that's when you strike. If you know you are going to die remember to run towards the person so hopefully you might kill them with your passive. One time I played karthus they had a AFK from start and she was Ashe every time i ulted i got a kill ended up with 38 kills that match because she got me fed. If you like remember to vote up.

At the end you can sell your Sorcerers Shoes for a fifth Archangels or keep them its up to you.

Pros:
Easy kills/assists.
People forget about his passive and die because of it.
Gets lots of multi-kills.
Can sometimes one hit people.
Cons:
Very squishy .
Veigar can one hit you.