True damage
The latest patch made a few champions who were able to previously increase the true damage, unable to do so now.
A quote from the patch notes:
"Damage amplification abilities no longer work on true damage
Abilities affected:
Poppy (Diplomatic Immunity)
Swain (Torment)
Talon (Cutthroat)
"
So these champions can no longer increase the damage of true damage, right? True damage was never supposed to be changed in any particular way - decreased or increased.
Interestingly enough, the new changes to Ahri contradict that. Her Charm increases the true damage portion of her Q.
Source
Why is she able to increase the true damage which is never supposed to be increased or reduced?
was (and is) specifically designed as an Assassin, and is highly dependent on her Orb for a lot of her damage output (especially when she's playing mid lane, she needs a strong poke.) She doesn't have the survivability of Poppy, Swain's Slow/Immobilize effects, or Talon's Teleport/Invisibility (Although her Ult is three Dashes, it's on a fairly long cooldown.) so she needs her Orb to be as powerful as possible (since it's also her main spell, every Ahri player will agree she'd be pretty much screwed if she didn't have her Orb.)