Use Graves's strong early clear and dueling to disrupt Karthus's vulnerable early jungle tempo.
Prioritize river control and contest Scuttle when your lanes have priority to deny Karthus safe farm and vision.
This is a snowball vs. scale matchup; leverage early tempo leads to prevent Karthus from reaching his late-game global damage power.
Jungle Plan
Path for fast clears and invade Karthus before he finishes his first full clear to force him off camps.
Use lane priority to control river entrances before dragon or Rift Herald setups, denying Karthus safe objective access.
Counter-jungle when Karthus shows on predictable gank paths or after he uses (R) to punish his cooldown.
Danger windows
Respect Karthus's early full clear tempo; invading too late risks running into him with full health and smite.
Avoid isolated river fights where Karthus can stack (Q) and slow you with (W), especially without lane priority.
Be cautious contesting objectives when Karthus has vision and his (R) is available to finish off low-health allies.
Early game
Start on the side with better leash and path camps to hit level 3 quickly and look for an early invade on Karthus's slower clear.
Contest first Scuttle only if your nearby lanes have priority to avoid getting collapsed on.
Avoid extended river fights without vision as Karthus can punish overcommit with his (Q) and (R).
Power spikes
At level 6, Karthus gains global damage with (R); avoid extended low-health fights and use (R) cooldown windows to counter-invade.
Graves's item scaling and fast clears boost his dueling and objective control; use this to cycle camps and contest before Karthus's first AP item spike.
Use your (E) dash and (W) smoke screen to outmaneuver Karthus's slow and poke damage during skirmishes.
Win conditions
Convert early clear tempo and strong dueling into aggressive counter-jungling to deny Karthus farm and delay his scaling.
Use vision and lane priority to control dragon and Rift Herald, forcing Karthus into unfavorable fights.
Apply pressure through ranged skirmishes and invade windows to keep Karthus under farmed and unable to impact fights with (R).
Tip: For Graves vs Karthus, read overview, trading pattern, and danger windows first for a fast Jungle lane check.
