Staff of Shadows question (corrected)

[Staff of Shadows question (corrected)]

I repost it with the correct text color!

 

If Overlord has the Staff of Shadows, can he use it to reroll one of his dice, or he can only force the heroes to reroll their dice?

Also, can Overlord use the Staff anytime (for any creature he controls, for every attribure test the heros make etc) or only when the lieutenant wielding the relic is involved? (he is attacking or defending himself)

Thanks!

[Staff of Shadows question]

If the Overloerd has the Staff of Shadows, can he use it to reroll one of his dice, or ha can only force the heroes to reroll their dice?

Also, can Overlord use the Staff anytime, or only when the lieutenant wielding the relic is involved? (he is attacking or defending himself)

 

Thanks!