Hi,

If during an encounter against the siren an hero with 1 fatigue has a rest order at the start of his turn can he pay first 1 fatigue for the siren an than recover all fatigues?

What's the exact wording of the Siren's ability? I would say no, since for other effects usually the Rest restores fatigue "at the start of his next turn", to me meaning before anything else. Though I believe there's a FAQ ruling that if more than one effect happens at the start, the hero can decide which order they happen (for example, if a hero rested while burning, he can recover his fatigue before rolling for burn).

-shnar

The card of siren states:

"[...] At the start of each hero's turn, that hero must either spend 1 fatigue or roll 1 power die. [...]"

Both effects (Siren's Call and use Rest) activate at the start of the turn. Therefore, according to the FAQ, the active player may choose the order in which they resolve.

So yes, you can pay for the SIren and then recover all fatigue.

+1 for the guy above quite simple as the OL and player you get to choose in which turn you make your start of turn happen.