Jax vs Karthus JUNGLE Matchup Guide | LaneStomp

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Jax

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Jungle

Karthus

Jax vs Karthus

Updated Jun 6, 2026

Overview

Prioritize disrupting Karthus's full clears by invading early since he lacks early dueling strength and mobility.
Use your medium mobility and (E) stun to contest Scuttle and river control before Karthus can safely farm.

Jungle Plan

Invade Karthus during his early clears to force him off camps and delay his item spikes.
Prioritize controlling river vision and contesting Scuttle to set up safer ganks and counter-ganks.
Use your dueling strength to counter-jungle after level 3, focusing on camps that Karthus will likely path to next.

Danger windows

Avoid isolated river fights before level 6 where Karthus can use (Q) and (W) to kite and slow you.
Be cautious contesting objectives when low on health or Smite, as (R) can finish off weakened enemies.
Respect moments when lanes lack priority, as Karthus can capitalize on poor vision to safely farm and scale.

Early game

Start with a three-camp clear optimized for level 3 power spike to enable early invades against Karthus's vulnerable full clear.
Contest first Scuttle when nearby lanes have priority to deny Karthus vision and objective control.
Avoid prolonged river fights if lanes cannot assist, as Karthus's global presence with (R) punishes overcommitments.

Power spikes

Level 6: Your (R) significantly boosts durability and damage, enabling extended fights where you can punish Karthus before he fully sets up.
Two-item spike: Your sustained damage and survivability outscale Karthus in side-lane duels, allowing you to pressure objectives and force responses.
Karthus's first AP item and level 6 (R) increase his global threat; use your early power to deny his farm and vision before this point.

Win conditions

Convert early invade leads into sustained counter-jungling to deny Karthus's scaling and force him into defensive farming.
Secure early Scuttle and dragon control with lane priority to limit Karthus's objective influence.
Use your scaling dueling power to pressure side lanes, forcing Karthus to respond and creating opportunities for your team to take objectives.