This game needs a replay feature to help understand what happened after a game. I was middle of the pack with an unexceptional blend of brawn , warriors and ferals, and one of the other guys had full primordial plus crystal maiden. He destroyed me each time we fought, but I was holding my own against everyone else, so I thought "ok, I can aim for second place". Final game, just him and me, he beats me on my board, I have a little HP left, and... I win. Somehow my units win on his boards, and he must have lost much more HP to the other players without me noticing... But yeah, it feels a bit underwhelming to win without knowing why.
My best bet would be Sand King with blink dagger immediately targeting his AW by chance while not being targeted, then him rushing through his back line stunning everyone at the perfect angle. Blink Sand King has been surprisingly handy when I don't get anything better.