As karthus, You will be able to blow up squishies with your Ultimate e with ease now. Even if they don't die, they will be too chunked to participate in a team fight.

You will be able to burn through the entire enemy team with proper positioning. Your 1 combined with your n will be able to one-shot enemy squishies. Use this strategy during neutral, objective fights.

Remember that your n placement can make or break an entire team fight. Place it well and from the fog of war so that the enemy team doesn't anticipate it and take necessary precautions beforehand. As karthus, You will be able to blow up the squishes with your Ultimate e with ease now. Even if they do not die, they will be too big to participate in a team fight. You will be able to burn through the entire enemy team with an appropriate positioning. Your 1 combined with your n will be able to shoot enemy squishes. Use this strategy during neutral and objective battles. Remember that your placement can make or break an entire team. Place it well and fog of war so that the enemy team does not anticipate it and take the necessary precautions in advance.