Ok the jungle thing is just absolutely wrong. Karthus clear is so fast that you finish doing your camps before enemy jungle can even come. You can’t be invaded on gromp. Getting invaded on red is possible but vs a lot of champs you can clear red before they come to you, and if you are really that scarred you can ward for it at 1:10. A lot of games I see enemy jg try to invade me at red but they see it’s gone and I’m just about finishing krugs by the time they check. Realistically in a ranked game the full clear is on average 2:55/2:56 but with leash I can be done by 2:50. It’s actually really nice, but karthus jungle has other issues which makes him really not the best right now when he is usually a sleeper S tier pick. Also it’s practically impossible to ever buff karthus jg since his bot lane is so strong, there is no way to do it. Tbh I would want his lvl 1 ult to do 50 more damage because since durability patch, it does literally no damage unless you have dark harvest.