Eagle sight cancelled by I am legion, while Tenebrous form is in play

The follwoing situation:

Azaneal annouces an bleed
Preys announces a block
Azaneal plays tenebrous form Superior
Prey declines to block
Predator plays Eagle Sight superior with Alexandra, wich forces a block attempt
Azaneal plays "I am legion" to cancel Eagle sight

is the blood still burned?

All I could find so far is that Hazimel/Enrage announce cost is paid after "as played", but sicne these are Actions, these might be different then for Modifiers and Reactions.
groups.google.com/g/rec.games.trading-cards.jyhad/c/07gUFmSeIxU/m/yIrwcMsATB4J