New answers tagged dishonored
If not interested in trainers, no, there are not any ways to cheat in Dishonored. The debug console was removed prior to release.
The symbol is not different, it is, indeed, his Outsider's mark. Here's a screenshot I just took of Daud's mark in the situation you described: If we look closely, we can see this is indeed his Outsider's mark. Outsider's mark provided above for comparison.
As long as you don't interfere, that's fine. Kills only count if Corvo or Daud killed the person. This does include indirect kills such as through rewiring arc pylons or feeding unconscious bodies to rats but letting NPCs butcher each other is fine.
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