LoL Karthus players may find him to be a confusing character to build out properly. You will find that his build changes when he is fighting either generic or specialized team compositions, demonstrating you shouldn't take the same Karthus build every single round of League of Legends
The most essential items to use in your champion's build include: Dolore di Liandry, Copricapo di Rabadon, and Bastone del Vuoto. Those who included these pieces in their builds had a significantly better winrate than players who used other item builds for Karthus. Likewise, if you are playing a mixed enemy team comp, you should really consider grabbing yourself the Ispirazione, and Dominazione runes. In recent games, he won the greatest fraction of his rounds when built with these runes.
We established our Karthus build recommendations by analyzing 19.947 recently ranked League games with him selected. We only advise the top winrate Karthus builds that were built by ranked LoL players enough times for us to reccomend them. With so many rounds in our data, we are confident in our recommended builds.