Do triggers on the chain still resolve if the permanent that put the trigger on the chain is removed from the board in response? Specifically, if Volibear attacks (placing a 5 damage trigger on the chain) and is then removed by Hidden Blade, does the 5 damage trigger still resolve?

Ruling: No, the 5 damage trigger does not resolve if Volibear is removed from the battlefield. Because Volibear's ability references "here" (the battlefield), when Volibear dies the targets become invalid since he is no longer at the battlefield the original targets were at.

Sequence:

• Volibear attacks, placing the "deal 5 damage" trigger on the chain
• Hidden Blade is played in response, removing Volibear
• Hidden Blade resolves, killing Volibear
• When the 5 damage trigger attempts to resolve, the targets are now invalid because Volibear is no longer "here" (at the battlefield)
• The trigger fails to resolve

Nuances:

• This ruling depends on the ability referencing "here" or the stats of the permanent itself - such effects won't resolve properly if the permanent is removed
• Effects that target a battlefield or a different unit (without referencing "here") would still resolve fully even if the source permanent is removed
• Targets and split amounts are declared when the trigger is added to the chain, but validity is checked again at resolution