Very very easy if you just focus on first reproduction,then speed and finally agility.You will have 3/4 off the map under your control before engaging in battle and there you can just overwhelm anyone with the superior numbers
death:you can do the melle only challenge on only the ruined smithy story quest.Also,it is quite plain-forward.just dont use any units which have the magic/range trait(like using only melle trait).all 10 waves there are non-flying.
possible glitch:one of my hero got some 3 xp after a quest,although i did not even use him(actually used only one).
He had loot,steel,life+2 & gold +1,if that has any effect.Or may be it was carried forward from the previous time i did it as that was my trial quest to see how the units work.
 "The Last Stand 2"){kind=icon}
 "Phage Wars 2"){kind=icon}
 "The Company of Myself"){kind=icon}
 "Protector IV"){kind=icon}