I just had the opposite problem: Around turn 40, right after I founded Avalan (2nd city), Vetrar + 2 brutes came looking for me (or the shard adjacent to my 1st city). My L6 Tandis + 2 dwarves + 2 pikemen were estimated to have "crushing defeat", but Tandis wasting 1 turn on Inspire (+15% dodge) actually made Vetrar miss almost half his (many, many) swings. (Vetrar must have Initiative 30 or so!!) Halfway through, it occurred to me: oh duh I might as well cast Graveseal on him for yuks and more testing -- and then he killed the 4 peons first, and Tandis won Vetrar can one-shot for 120+ hp damage, ugh. I unlocked the achievement for beating a "crushing defeat" odds
Seriously tho ... it's a tad unfair to have Vetrar attack my 1st city when I'm still having trouble with Medium huts. Saved me the bother, tho. Tandis alone is actually faster by +1/turn, neener -- I might keep him that way and just solo a bunch of strongholds.
I love the lieutenant on an island. I've started on an island before, so I think the lieutenant groups can never paradrop there (because they start on the map). The sadistic DM can just paradrop monster rings onto your island, tho.
The DM should allow lieutenants + SK's strategic map magic to slowly construct a mole (spit of land connecting the mainland to an island city), e.g. by tearing down nearby forest hexes. Alexander the Whodat did this to the (formerly-a-)fortress city of Tyr, and after a few weeks their citizens stopped laughing when it became clear to both sides that it was working, and would inevitably succeed. (Today the "mainland" simply includes all of what used to be Tyr, and Alexander's land spit has had numerous roadways constructed upon it, including the modern highway.) After that, he was Alexander the Not Bad ...