Lux vs Karthus

Not enough games

High burstHeavy pokeCountered by stasisHeavy AP damage

Build vs Karthus

The champion's reference build, for lack of enough games in this matchup

Starting items

—

x2—

Core build

1—

2—

3—

Standard

4Magic pen

5—

Summoner spells

100%

Anti CC

4vs CC

Other options

—

Domination

Dark Harvest

Cheap Shot

Grisly Mementos

Ultimate Hunter

Sorcery

Axiom Arcanist

Scorch

Strength by game phase

Passive, spells and ultimate

Death Defied (P)

Upon dying, Karthus enters a spirit form that allows him to continue casting spells.

Cooldowns by spell rank

Level	Q	W	E	R
3	0s	15s	0.5s	–
6	0s	15s	0.5s	3m20
9	0s	15s	0.5s	3m20
11	0s	15s	0.5s	3m
16	0s	15s	0.5s	2m40
18	0s	15s	0.5s	2m40

Tips to maximize your impact

Start with Light Binding
Start with Light Binding (Q), then Lucent Singularity (E) and Final Spark (R) before detonating the singularity: the root makes sure everything hits.
Weave an auto between spells
Slip in an auto after each spell that hits: it triggers Illumination (passive) for extra magic damage, and Final Spark (R) triggers it too.
Light up brush with your E
Cast Lucent Singularity (E) into a brush before walking in: the area is revealed, and a hidden enemy would be slowed.
Shield your allies twice
Cast Prismatic Barrier (W) through as many allies as you can: the wand shields them on the way out, then again on the way back.
Use your R often
Cast Final Spark (R) to clear a wave or secure an objective: it only has a 60 to 40 second cooldown, depending on rank.

How to counter and exploit weaknesses

Stay near your minions
Stay near your minions or your allies: Lay Waste (Q) deals much more damage when the blast hits only one enemy.
Jump on him if you can
If you can engage, jump on him: Karthus has no dash or leap to escape.
Don't stay low once he hits 6
Once he hits level 6, back instead of staying at low health: Requiem (R) hits every enemy champion wherever they are, 3 seconds after he starts channeling.
Save your protection for Requiem
If you have a shield, a heal or invulnerability, save it for Requiem (R): it hits every enemy champion 3 seconds after he starts channeling.
Move away after he dies
Once Karthus is dead, move away: Death Defied (passive) keeps him in spirit form for a while, and he can still cast his spells.

Patch 16.21.1