They're massive monsters that require the souls of dozens, if not hundreds of people simply to be summoned, though they only need to do so once, if their user summons them in a later duel they draw on the souls already imprisoned
On Turn 2 or later, "Absolute Dragon" can Summon out "Odd-Eyes Rebellion Dragon" which can then be used as material to directly Xyz Summon "Odd-Eyes Rebellion Dragon Overlord" for an OTK with its three attacks
Consider Everlasting Torment as a useful tool against Oloro, Ageless Ascetic in Commander
There are some things like Keranos, God of Storms, Grave Titan, or Vendilion Clique they can board in that might help them, but you should be able to defeat those cards
Salamangreat Sunlight Wolf three beats, one identity Spell and Trap Names Work Differently Monster names are nouns
The first two of these will be Demise True Draco builds and the third will be an Invoked True Draco build