Averaging one trigger per cast is going to be good enough for the Duelist
The unique selling point is brutal simplicity , making Atarka ideal for players who want straightforward, lethal Dragon combat without complex setup or combos
Sacrificing a Hidden land or a Promising Vein can help you get that end step descend payoff
The main commander options are Davros, Dalek Creator who true to his name makes Daleks, but also forces discards or card draw, or Missy, who turns everything that dies into Cybermen, and causes them to deal damage to your opponents
Doctor's companion (You can have two commanders if the other is the Doctor.) The token you create copies the original characteristics of the token as stated by the effect that created that token (unless that token is copying something else
If it wasnt, you get to replace that creature with a 2/2 Detective token