Thrassian claws and bite striking magical creatures?

So I’m building a Thrassian class and I noticed the Thrassian gladiator can strike magical creatures with their claws and bite beginning at 5th level, but I can’t find this in the class building section of the Player’s Companion.

Can all Thrassians do so beginning at 5th, do they need to fight as monsters to do so (at least 3 points in fighting value), or is it a custom power?

Anyone? Anyone at all with an idea about this? Am I missing something obvious?

I’m NOT an Autarch, but personally I’d allow a Thrassian to do so at level 5, otherwise the claws and bite become much less useful at higher levels.

ACKS, p. 104: “…monsters with 5 HD or more are able to affect these monsters through natural ferocity.”

ACKS, p. 149: “…the term “monster” generally refers to any being other than the player characters.”

With that said, I house-ruled it for my campaign: any creature with 5 HD or more, including class levels, and a non-subdual attack, can deal damage as if magical. I.e., fists and kicks won’t cut it, but a sword would (just like a giant’s club), and a thrassian’s claws or a mystic’s unarmed attacks would.

At 5 HD any creature’s natural attacks can strike as if they were magical (ACKS p 104). When I asked Alex, he said he’d allow characters with the Unarmed Fighting proficiency to do the same at 5th level.

Makes sense. Thanks guys!