Death Defied
(Innate): Upon dying, Karthus enters a spirit form, which allows him to continue casting spells for 7 seconds. During this time, his abilities cost no mana.
Tips :
Karthus's spirit casts spells.Even in death he continues to cast spells without any mana cost!
Karthus can continue to do his spells after death but he cannot move about, it is essential that you position yourself well before dying.Make sure that you don't wait too long before you cast your ultimate, you can't cast it just before the end of the 7 seconds because Karthus must channel it for 3 seconds. You should cast it before the 4th second of the passive!
Since you are spirit form, it is not possible to interrupt Karthus as he channels his ultimate. It is sometimes a good strategy to die in the middle of a teamfight so that you can be sure that you can use your ultimate without being interrupted.
Spells are free when you are dead so it can be useful to die if you have no more mana in a teamfight with the aim of casting your ultimate if it will make a difference etc... Also when Karthus takes damage in teamfights his teammates take less.
If you play against a Karthus it is essential that you leave the zone he dies in.
Lay Waste (Q)
(Active): After a 0.5 second delay, Karthus blasts target area at the cursor's position, dealing magic damage to every enemy in the area. The damage is doubled if it only hits one unit.
Tips :
Harass/push, the multi-purpose spell
The spell that lets you farm at distance!
Karthus can farm much more easily with his bomb than with his auto-attacks, so he misses very few last hits in the lane from level 1. To last hit with the bomb you need to place it so that it only hits the desired minion, otherwise it will reduce the damage.This spell takes a bit of getting used to because it is a "smartcast", meaning that you don't need to left click before you cast it.
It is Karthus's main spell to harass his opponent in the lane phase, as well as to kill him after slowing him with the W and aid the skillshot.
It is always easier to use the spell when your opponent advances to last hit!
This spell also gives you vision, letting your check the bushes and avoid having to facecheck.
Cost: 20 / 26 / 32 / 38 / 44 mana
Magic Damage (Multiple Target): 40 / 60 / 80 / 100 / 120 (+0.3 per ability power)
Magic Damage (Single Target): 80 / 120 / 160 / 200 / 240 (+0.6 per ability power)
Wall of Pain (W)
(Active): Karthus creates a wall between 2 obelisks at target position for 5 seconds. Enemies who pass this wall have their movement speed reduced by a large amount and their magic resistance reduced by 15% for 5 seconds
Tips :
Karthus creates a purple wall in the targeted zone.A slow spell and a magic resistance reduction
When your jungler ganks in the lane with Karthus he can use the wall to slow his target and potentially follow up with his exhaust to make a kill. The slow helps to place Karthus's Q more easily.This is a good engage for a teamfight, Karthus must hit the maximum number of opponents.
It is possible to place the wall directly on the opponent to immediately apply the slow so that he can't dodge. The range of the spell is also big.
If an opponent goes back through the wall it does not refresh the duration of the debuff.
The wall gives vision in the zone it has been created in, meaning you can also avoid facechecks!
Wall Length: 800 / 900 / 1000 / 1100 / 1200
Maximum Wall Sight est.: 1300 / 1325 / 1350 / 1375 / 1400
Slow: 40 / 50 / 60 / 70 / 80 %
Defile (E)
(Toggle Off): When Karthus kills a unit, he restores mana.
(Toggle On): Karthus surrounds himself with the souls of his victims, dealing magic damage per second for a high mana cost.
Tips :
The zone around Karthus here is showing that you'd better get out the way!Some DoT around Karthus and some mana
A very efficient damage spell in teamfights!
This spell lets you deal zone damage in teamfights, even after your death.The spell activates itself automatically once dead and can't be deactivated if Karthus has put at least one point in the skill.
The spell's passive lets Karthus farm with his Q without losing too much mana.
Defile can quickly push the lane and let Karthus move or do the wraiths.
Defile can let you last hit because the damage is instant and the mana hit per second is quite low. Note that at level 1 this spell does not do a lot of damage.
Advanced Tips: because of the immediate damage from this spell, with a 40% CDR, Karthus can increase his damage per second by activating/deactivating the spell quickly more than once a second!
Mana Restored: 20 / 27 / 34 / 41 / 48 per kill
Cost: 30 / 42 / 54 / 66 / 78 mana per second
Magic Damage: 30 / 50 / 70 / 90 / 110 (+0.25 per ability power)
Requiem (R)
(Active): After channeling for 3 seconds, Karthus deals magic damage to all enemy champions regardless of distance.
Tips :
Karthus raises his arms and a red trail on your enemies shows that the ultimate is being channeled!An ultimate that touches the whole map!
Kill them all!
Karthus' ultimate lets him make kills while staying in the mid, you must keep an eye on what is happening on the map to watch out for an opponent who is low on HP.Karthus can also use his ultimate before a teamfight if the enemy team doesn't have anything to heal themselves with or a shield.
Karthus' ultimate puts a lot of pressure on the enemy team in the lane phase and players tend to forget about it.
You can get interrupted during the incantation of the ultimate.
There are spells that let players avoid the damage of your ultimate.
Cost: 150 / 175 / 200 mana
Cooldown: 200 / 180 / 160 seconds
Magic Damage: 250 / 400 / 550 (+0.6 per ability power)
Pros
Has great late game damage and can sit in the middle of the enemy team as he has 7 seconds to continue damage after death.
His Q allows him to farm easily without using a lot of mana as his E returns in upon kill when it is not active.
His ultimate allows him to assist other lanes without even leaving the mid lane.
Cons
Needs to die in a good spot ot be able to continue DPS after death.
Can easily get behind in lane if killed and is hard for him to dominate lane phase other than with farm.
Hard to stop opponent from roaming or playing aggressively if his opponent plays correctly.
His ultimate has a long cooldown so if It is interrupted or wasted in a fight without resulting in a kill it will take a while before it is up again.
