I can use the special power of my rank when I reveal my rank number. My question is this:
can I use my power at any other time?
No (Unless the Alchemist helps you).
Or can I use it only once?
Only once per game (Unless the Alchemist helps you).
And if I decide not to use it the first time, can I decide to use it in the next rounds?
You have one chance to optionally use it. If you pass on your one chance you never get another one (Unless the Alchemist helps you).
Or can I use my power every time I get a wound?
The 2, 5, and 7 would be very very overpowered if they could use their abilities like this.
Thanks for your help!