Hi just to verify :

can Tahlia HF : "Use when a monster starts its activation or moves into a space adjacent to you. Immediately perform an attack that targets that monster. After the attack is resolved, the monster's activation resumes"

and First Strike from Wildlander : "During the overlord's turn, immediately after he chooses a monster to activate, you may exhaust this card to perfom an attack targeting that monster with a Bow. After this attack is resolved, if the monster was not defeated, it may continue its activation."

be used on the same monster?
I think yes...

If I'm true I have another question : for me both powers have the same trigger... so should both powers be used can OL (as he is the active player) choose the order in which they are triggered ? or are the heroes to choose ?

If hero activates both on same trigger (start of activation of 1 monster), OL would choose order I believe.

While I would agree with Zaltyre in principle, I think this should basically never happen.

After all, when the OL activates the monster and/or begins to move the monster, all the heroes have to do is say wait, and then discuss/plan what would be the best order to perform either the heroic feat and/or class card (First Strike) in this case. They don't choose to do them at the same time, and this way, the OL doesn't get to choose which goes first.

Given this, I would almost always choose to use the class card skill first, so that you can save your heroic feat, as it is a limited resource.

Thank you for your answers.

any2cards, but if Tahlia doesn't declares the use of it's HF from start could it be declared latter? is it always the start of activation after First Strike ?

The final goal being able to use both to try to kill a monster that can't be one shotted... but the order could matter ..

35 minutes ago, Felin said:

is it always the start of activation after First Strike ?

I would argue that after the First Strike attack resolves, the timing window of "a monster starting its activation" remains open until the players decide to no longer use any other abilities with such a timing. This allows the Tahlia player to decide whether to use their Heroic Feat or not.

5 hours ago, Charmy said:

I would argue that after the First Strike attack resolves, the timing window of "a monster starting its activation" remains open until the players decide to no longer use any other abilities with such a timing. This allows the Tahlia player to decide whether to use their Heroic Feat or not.

I completely agree. This was the point. Just because 1 player uses an ability or class card that triggers on a monster starting its activation, doesn't mean that that monster's starting of its activation has ended.