The set up JoinMe recommended with Kymar could work.
You just have to build your Coldhearts with 100 more Speed vs. Kymar.
You would need your Coldhearts to move 2 times before Kymar has a turn.
2 Coldhearts, Royal Guard, Miscreated Monster and Serris
Its another set up you can do which should win in around 1 min.
The set up I am recommending doesn't reset skills.
It just uses M.M Big Shield to stall the fight till the Coldhearts skills come off Cool Down.
You will do 3 nukes.
Put Big Shield + Survive few hits.
Than cycle back to do another 3 nukes.
Just make sure your Serris has lower HP vs. your Coldhearts so the Baby Spiders target Serris.