OK so first run at Ancient Wood Legend with mono red back when it started bombed out at Imps, just fucked up stalling on the way there.
Second run a couple days later I got beyond them and fucked up something around wave 8, not even sure what.
Today went in with Ares helper. Stalled OK and got Green/Red imps, Echidna was up after 1 round of imps. Used her and PKH, burned down Green and worked down red NP. Little more stalling from 6-8, used PKH again on Siren. Worked her down steady and easy and she never healed. First burst on boss got him down to about 40ish before he started attacking(Menace, self buff etc). Beat him up some more using all my cooldowns. Going great, get him to an absolute sliver of health and boom, 5turn stun on all my fire guys(everyone). Suddenly go from 27k HP to 9k, fuck. Dead next attack(asshole even did the big attack). Fuck it, burned stone and killed him. Will get stone back from finishing the others.
Still, another big reminder that I need to finish leveling my whole GD team up.