Michinaki is an amazing champ for hydra, I'd max him out.

If i pulled a dupe michi I'd immediately build him too to put on a 2nd team :)

Vogoth is great for survivability in DT and for arena go-2nd teams

I would make my first priority unm cb team before any of this other stuff.

I have to low champions to make good unm. 

I have only 58 lvl. Make 18mln o hard(power team is 240k i know that it would be 30 mln). 

Edit:

I maxed wallmaster othorion(could be make solo spider 20, make 500k dmg on hydra, 7 mln dmg on demon lord). 

So i passed doom Tower hard (current lvl 19) Make 2.6 mln dmg with 3 keys. 

But still i staying on arena Gold 2. I will make a Photo and send my team here and stats. Maybe some can help me. 

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Now it looks like this what i need to do to got in Gold 3 arena(at least)? 

youre gearing your champions wrong. I would auggest watching youtube videos on how to gear for each role.

A big starter would be if the boots are not main stat speed get rid of them.