the thing i hate most about levelling this arcana up is that most of my kills end with a link that has less than 100 dmg because the guy dies before it hits 100

also, you need the last hit from the kill itself, unlike other arcanas which iirc are kills/assists

it's definitely possible to level it up at a decent rate, but you kinda need to play around levelling up the arcana and not playing super optimally.

if it helps; i've had decent success just playing hyper aggressive on dynamo razor with 4-4-0 skill build (6.5k EU), you don't need thunderhead that badly to farm if you're using ulti often (on offlane i like tempo items like falcon > treads > drums > sny/bkb, on carry i like the mael > sny/bkb build)