when he went to port your marsh, that was the beginning of upkeep right? So the chevill ability is on the stack? and you cant play the ability in response?
I would say there isn't any playable combination these days. Due to Uro leaving the format, Leovold got pretty screwed since Uro was a tool to deal with fast aggressive decks f.e. Winota. Apart from that, I expect Esior to be banned very soon so you might take your time to brew the turtle?! :P