How would Arcane Comet work with Karthus ult?

I would assume it works the same way as . If it does, it hit's whomever is on top or your tab-list

it only launches one comet even if you hit multiple enemies simultaneously.

it might still target the enemy you have placed higher on the score screen.

That makes sense...when I was double hitting adc and supp (i'm supp playing mages usually), it would hit the adc, and i always put them tops on my list so i can see how my adc's cs compares at a quick glance.

NA XD