I had a situation in the last quest | could not find the answer anywhere... A hero was poisoned, with 1 HP left, he did not roll a successful atribute test, so he took 1 dmg and became KO'ed at the begining of his turn. Will him lose his whole activation or could he make a stand up action with the rest of his activation?

No, he cannot stand up during this round. He has had a start of turn, when he is defeated, his turn ends. He cannot have multiple starts and/or ends of turns in a single round. He could be revived by another hero this round, but his turn has already passed.

I did something similar to a hero last week, but it was a reaction to his first action.

Roger that Zalt. So I acted correctly in the last quest we played. Tyvm!

Rulebook - Knocked Out, Page 15 "Unless revived by another hero, a knocked out hero may only perform one action on his next turn, and that action must be to stand back up"

Oddjob, I am aware of the corerules, but they were supposed to work when the hero gets knocked out at the OL turn. That would fit perfectly. However, In my example the hero got KO'ed at his very turn, at his begining phase, and, his 2 actions were still unspent. So, the gap in the rules remained still.

Following literally the rulebook, we would have the hero to perform a stand up action in the very turn he got KO'ed, but Zalt pointed the exact detail I was not seeing: the fact wich the turn of the hero imediatelly ends when he gets KO'ed.

So, in my opinion, rulebook pg 15 were not enough to fulfill the whole question.