NotEnoughTime

I believe that the whole Odiums champion is a red herring from Brandon Sanderson. I think i all comes down to part in the contract that says "otherwise unharmed by either side's forces" There are plenty of other factions that don't side with Odium or Dalinar, that would be willing to harm Dalinar's "champion". Take for example Ishar. He already believes that Dalinar is Odium's ally/champion. All Odium has to do is trick Ishar into attacking Dalinar and boom, instant advantage. This is of course just a simple theory, but I like it