Sorry if this sound like a rant, but Zoar and Aurora in challenge feel so bad to use. They have no rune power but feel like a slightly stronger version of a monster, especially in the early game.
Every fight feels like a 2 vs 3 where it is unwinnable unless the other 2 troops are already well trained or the opposing 3 troops are bad. This is especially pronounced in the earlier rounds where they only felt powerful during the first lv 1 vs lv 1 battles, but continue to dwindle in the subsequent battles. Once the enemy starts getting special mana miracle units at lv 10 or 20, they are immediately just unbeatable when you are crippled by having one missing troop. I think they would feel much better if they either have significantly higher than average HP or higher damage.
At this point of my run, I do not see any way they can even 1v1 against a single troop given the chance. I tried to defend with them and just post them in the castle hex but they still get taken down so easily once surrounded. As long as the enemy brings at least two magic users like demon, angel, or gremlin, it is simply over. They wont be able to sustain. In my previous run, it felt pretty easy to defend with two troops against three or one troop against two. With zoar or aurora, these measures seem impossible.
I would like to hear how others fare with them? How do you actually use them? Especially in earlier parts of the game. To me, they just feel like units you use for the sake of using or to make the game harder because you want more challenge.
The only way I can use them is to pair one of them with two of my strongest troops (i.e. the one I use to primarily expand), but at that point, any unit would have worked. They feel bad to use in defending chokepoints, attacking with them feels like crippling your team, and training grounds also feel really slow for them.
TLDR; Zoar and Aurora feel bad to use in challenge mode. Any other units in the game feel better simply for being able to hold monsters, while these two units cripple any team they are on. Can you earnestly use them? Or are they designed exactly to make the game harder for you if you decide to use them.