Seems like there's a lot of topics dedicated to clarifying how Hoax's invisibility interacts with other characters' abilities. Well, here's another one!

So, do abilities and equipment that initiate Mental Duels (such as Heizinger's Sha-Na-Ra) affect Hoax while her invisibility is active? I was tempted to just rule against it, until I realized that Bull Rushes, which do affect her) also count as duels.

Any clarification would be welcome.

It's a little while since this question was asked, but nontheless I'll try to answer it.

Hoax may be not declared the target of an attack while she is invisible.

Sha-Na-Ra and other mental duels or test like Itami's Demonic Bellow does not declare her the target of an attack, so they will affect her.

Thematically you can think of it as her mind is still reachable even if you don't know where exactly she is.