Explaining it as simply as possible, talents happen when they say they happen. Page 2 of the rules reference specifies in the
Attack section that if a
talent is triggered when attacking, its effect occurs simultaneously with the
damage being dealt, and if a
talent triggers after attacking, it occurs after resolving the
attack and
retaliation if it is not defeated. If a
talent says it happens as a result of moving onto a specific
hex, the
talent triggers right after the
unit moves onto that
hex; it does not wait until the full
movement is over. If something triggers off of being reduced to 1
health, it triggers when the
unit reaches 1
health, keeping in mind that
attack and
retaliation happen back to back unless the
talent says it happens when attacking or that the
retaliation is skipped. For a specific example, say an AI Taproot has 2
health and 2
movement. It moves 1
hex and triggers Toxic Secretion, losing 1
health. It now has 1
health and so the Taproot's Summon is triggered. It does not finish its
movement, it uses Summon, and gets flipped and grouped under whatever it summoned. The new
unit also does not finish the Taproot's
movement or move itself, because the AI Summon
talent says it does not move this
turn. If instead the Taproot were reduced to 1
health from an
attack, the Taproot would get to retaliate first, because that is part of the
attack and Summon says after, and then it would Summon. With regards to the word immediately, its use does not usually have a special meaning. It is usually just used to emphasize unusual timing, but timing that would occur even if that word were not in the sentence.