I max one jackal for every holy sniper I max. So far I have 2 (+20 and +10) for my Joon and the fish king. If I get around to another Joon, I’ll max a third jackal. I love facing purple war tanks.
I’m on Jackal +2, which is likely where I’ll stop as it’s all I have. Likely the same with Mist (damn it should be Myst, don’t know why that’s bothering me so much) although I can’t guarantee until I actually use her.
Your choice is between a “must have” and an “excellent” hero.
Jackal is immensely useful in raids, titans, wars etc. Fragile killer so emblems are going to be needed if you take him up against 5* teams and anything above 8* titans.
Mist is “merely” excellent and deserves to be the follow-up project with little doubt. In a color that lacks top notch 4* depth you have managed to summon the two elite 4* so congratulations and enjoy them.
Both ought to serve you well even once you have a deep 5* bench and face heavily emblemed 5* teams.
The pairing would not be overkill for challenge bosses. Layer in a regular defense down and now we’re talking. Best buds with Wilbur, who seems to love to hang around the holy heroes already (he and my Wu Kong are tight).
Mist first anytime and all the way
Mist cripples and delays the opponent defense team much more than Jackal can ever do.
Mist can be a defensive tank if needed and does the job quite well.
Titan scores are also improved with Mist (Jackal is of course better on Titans for sue but still).