MArcomage

I really don't know, it was easy using rares (catastrophe, implosion, order of white lotus...) but now...
I can only suggest to use some common/uncommon banish to discard chaos dwarf, mountain sentinel and bank.
also luxory tax is quite useful. and you can duplicate it with halfing rogue.
other suggestions: gleaners and dark warrior

Finally I suggest to use condor to get rid of your useless rares. EDIT:(we don't have a card named condor, do we? I mean volture)

I've recently beat all 4 of them,(YAY for me!!) where Marquis was the most deadly with his supply of one-kill rares.

Grogful was the easiest, you just outbuild him, cause he does not touch your tower, just accumulates money.
Sophie too was outbuilt - while halfing her tower and lowering quarry.
Dementios was beaten by sheath your swords, plague, soul cleaver, cultists, and so on. Ending with ninja.
Marquis - the hardest s.o.b - with tons of luck, soul cleave, destruction, sheath your swords and very much wall++++. In the end I got tower 150.

One of the best moves for me was using sheath your swords (overpowered card) + halflings to make a reserve copies for this card.

Ah, I've beaten grofgul. you were right,the best strategy is to build your own tower.
Anyway now Grofgul is quite easy to beat since it has no more alliance cards and chaos dwarf is useless.