I've been using Stan's suggestion of Korvash, Amira, Spirit fox, Manticore. Unfortunately I still lose about 75% of the time. My Amira is not yet ascended, so she only does 30 damage on the first shot, which almost never one-shots justice. I also don't have Korvash's 3rd trait- I'm sure that helps a lot. I find spirit fox doesn't help too much. It only drains 7 mana and seems like they just fill it right up again. So I'm experimenting with other troops there.
Had some luck with
Unfortunately Korvash loses the first trait (3 to all in 1st position) by putting frostling up front. But don't want Frostling to get blocked. Idea is to try to freeze justice when it gets close to full. She webs him too, which dramatically lowers the boost he gives to his teammates. And double skull damage vs frozen and webbed enemies. Haven't found out yet if that effect stacks. On the downside, just a few skull hits wipes her out...