

Team-focused Karthus data from 1,633 Master+ coordinated 5v5 games, including Flex 5 and Ranked 5v5 data where available. This is not Solo Queue data. Karthus has an observed 50.2% win rate as Jungle in the current sample.
Items for the selected keystone (1080 games).
Most observed exact rune page per keystone.
Who Karthus beats and struggles against in Master+ coordinated games.
Karthus counters lists the best and worst picks versus Karthus in Master+ coordinated 5v5.
Build around Karthus Jungle: team style, supports and alternatives from Master+ coordinated games.
Data-backed notes from the Karthus Master+ sample on this page.
In LoL Tracker's Master+ coordinated sample on patch 26.20, Karthus is tracked primarily as Jungle across 1,633 games with an observed 50.2% win rate. These results come from Flex 5 and Ranked 5v5 team games rather than standard Solo Queue.
Karthus appears most frequently in Scaling Teamfight drafts across 1,072 observed games in that style.