I wonder if it would be feasible to say that Lyssa and Trenloe can use their ability to force a re-roll of the Stealth die. I know it is not mentioned on either of the characters, however, they were also created before the Stealth Die, and it would make Lyssa much more durable (if she drank a potion that is). However I supose Trenloe would be overly powerful, as he 'nearly' ignores Stealth then.

If you compare Trenloe to the other tanks, he is weaker anyway. Tahlia? Varikas? Nanok?? Even Steelhorns is better in my book. So, ol' Trenloe could actually use that boost. Considering that as far as I know, olny the Shades have Stealth, he would be attacking them with sub-optimal weapons anyway.

Likewise Lyssa will not change game balance much if she gets that boost, for, now, she is epic crap.

The only reason I can think of why Lyssa and Trenloe can't reroll red, blue, or white dice is that the designers didn't want them rerolling a die with an X on it. That precedent says that they probably shouldn't be rerolling the stealth die; that's also consistent with a strict reading of their abilities, whereas if the designers wanted them to reroll stealth dice, they ought to have made a note of that somewhere.

It's true that Lyssa isn't good, but I think that has more to do with her power dice than her ability. She's actually rather durable for her conquest value.

Lyssa's issue is dice, but it's also compounded by giving her a ranged weapon on the grounds that she's fast and vulnerable. With a ranged weapon she will never hurt anything, whereas with a sword and shield she can actually reach and take out lone monsters, especially with a good melee skill like Mighty.

I'd still let her reroll a Stealth though, simply because she is still significantly sub-par.

Trenloe's issue is that his ability very rarely acheives anything. Assuming he has any weapon with surge=damage, there iare only a couple of sides of either the green or black dice which are worth re-rolling since lack of damage tends to be made up for with a surge. However, Trenloe does have a chance to be using a stealth dice, if he finds himself with the Leviathan or Stone-Cutter swords. Now, even though they're both unlikely, and the latter he'll only have for a couple of turns at the end, I'd be tempted to let him reroll these, partly because he's crap, but partly because it's deligtfully thematic. The swords are likely to miss because they're heavy whereas Trenloe the Strong is... well, strong.

But sure, if we're going with either the letter of the rules, or what the designers intended, I'd say they can't.