Condition.
If Touched is attached to a:
Minion − Rogue's attacks gain overkill.
Villain − Rogue gains retaliate 1.
Ally − Rogue gains the AERIAL trait.
Hero − Rogue gains stalwart.
The signature card in Rogue's deck, how you use it each turn will determine some additional riders for the rest of her kit.
Most turns it will probably be on the villain, setting up retaliated, stronger attacks (if Rogue's Jacket is in play) and debilitating effects from Southern Cross or Goin' Rogue.
This also makes her Cyclops's best friend, as a free upgrade that you can drop on enemies every round, teeing them up for an optic blast.
Since this comes up often: Touched is considered part of your deck, and counts towards the min 40/max 50 card limit (i.e. Rogue effectively has 16 character cards rather than the usual 15). Ruling here: hallofheroeslcg.com
Yes, Death-Glow and Touched count toward their hero’s deck sizes.
This is why the Deckbuilder includes Touched as a 'proper' card in the deck.
Since the Setup phase occurs after mulliganing, this means that Touched should be shuffled into your deck at the beginning of the game, and can potentially be part of your initial draw or (worse) your mulligan. It's only set aside via Anna Marie's Setup ability after that, meaning that you can mulligan into it and be forced to accept a 5-card opening hand.
...This is frequently house-ruled away. Do As You Will is the whole of the law!