Rust lacks a perk?

[Lady Nasse]

So literally every aura and curse has a corresponding perk allowing you to apply more charges and even alter its effects... except rust? Why are there no rust perks? Am I just blind and somehow missing it, or was this overlooked when the new DLC was rolled out??

 

[SeraphAscending]

No, all the "special" new auras/curses lack perks.
This also affects Zeal and Scourge from Sands of Ulminin.

Those effects are primarily defined by their interactions with other effects. (zeal, burn to +damage; scourge, +dark-explosion-damage and chill to dark damage)
That's probably why the devs decided not to give them perks, since it would clutter the perk screen and would allow you to double tap on these synergies.

Rust already gets more valuable if you enhance the respective auras/curses. Scourge already makes dark and chill get more damage and zeal buffs you real hard if you have some burn (in addition to the other effects it has).