Karthus

low mobilty

high damage

Let us start with his passive.

Passive / Death Defied

"Upon Dying, Karthus enters spirit form that allows him to continue casting spells for 7 seconds."

Karthus

Q / Lay Waste

" Karthus unleashes a delayed blast at a location, dealing damage to nearby enemies."

a little bit

W / Wall of Pain

" Karthus creates a passable screen of leeching energy. Any enemy units that walk through the screen have their Movement Speed and Magic Resist reduced for a period."

E / Defile

" Karthus passively steals energy from his victims, gaining Mana on each kill. Alternatively, Karthus can surround himself in the souls of his prey, dealing damage to nearby enemies, buit quickly draining his own Mana."

R / Requiem

"After channeling for 3 seconds, Karthus deals damage to all enemy champions."

is aoutput champion who canpeople down in seconds. (If played right.)This is one of the reasons whyis overpowered. Even when you get killed in team fights, you still have 7 whole seconds to continue casting spells and trust me. They hurt.One of the strongest abilities in-game in my opinion. If you hiton a single target, the damage is doubled. That is why he can poke and burst champions quickly.Since patch 10.16 the AP ratio went from 0.35 to 0.3. This only affects the late game, but not that much. He still is a valid pick.This ability is amazing. No matter how much magic resist the enemy has, you can always damage them in combination withandGreat ability to sustain in lane! The Mana you get back after killing a unit is +- enough for 1 extra Q. In team fights you must activate this ability and keep it activated. Only turn it off if you are low on Mana. I would not recommend turning this ability on in early game since it will drain out your Mana quickly.An ability that deals 250 damage on its first level to all five players at the same time. This is a game changing ultimate. In combination with your magic penetration you can basically deal true damage on carries in late game. You have the possibility to one-shot them.Don't use your ultimate just to secure a kill. If your bot lane gets ganked by the enemy jungler or your mid laner, activate it! There is a high chance that the enemy team will back off since you dealt a lot of damage to them. This way you saved your bottom lane and maybe secured an assist for yourself! Or you can use it when you see your top laner / bot laners fight. Either way, teamplay is important!