For those of you struggling with this, I would say any hero can with eul's, just got 3 stars (60att 5spell) with Pudge ^^
Oracle in team seems to help with ult and I'd say it counts fountain hits while you eul inside, couldn't test very well but last 8 evaded attacks where eul's at fountain.
If I helps somebody, you can try the quest with anyhero that can use an Eul's (mb add crest or halberd)
For those of you struggling with this, I would say any hero can with eul's, just got 3 stars (60att 5spell) with Pudge ^^
Oracle in team seems to help with ult and I'd say it counts fountain hits while you eul inside, couldn't test very well but last 8 evaded attacks where eul's at fountain.
If I helps somebody, you can try the quest with anyhero that can use an Eul's (mb add crest or halberd)