What counter mechs frontline ?
I mean what I should use if I know my enemy is a dwarf and using mechs ?
In human and lich races
Scorpions only work if they are Gold or 2 or more levels higher than the mechs! This is coming from a dwarf player. Main counter is from a Human perspective, Cavalry. From Rakaan I believe the counter would be either turtle(to tank blaster and mechs, or the gold unit that has the Kick ability). From Lich, as I said, Gold scorpions but most of the time it's not worth having them, and even if you do you won't have more than maybe 2 sets which cannot cover the frontline... Your safe bet with lich is to try to stall the fight until Dwarf ammunition is empty, Mechs by themselves(unless golden and highly upgraded) do not do much damage unless you have Giant/Massive units. Once Dwarfs are out of ammo, you are depending on spiderlings spawned from Silver/Gold spiders... As a Human the only way that I have experienced can break Dwarf is with gold cavalry, with main research in the cavalry! When It comes to Dwarf vs Dwarf, you either go with Mech/blaster and depend on upgrades and troop buffs(from Jacq, Gafgar, Grimms and Nora) and basically both get crazy losses, or you go with the most unconventional way such as mech/miner and deadeyes... But I have only seen whale Asian players being able to pull that off 2-3 levels ahead of competition. Hope this helps.
PS: Rakaan is the only race that I am not too familiar with.