Diviner's Mask + Reap Spirit question

Hi guys!

I’d like to know if the 25% reduced res to Reap Spirit on Diviner’s Mask will get applied by only the player cast, only the Wraith’s attacks or by both.

And then i vaguely recall, that somebody somewhere mentioned, that the Wraiths are unkillable. If that was true, they would always last the full duration (and potentially reapply the RR debuff), but i can find neither a verification nor a falsification of that claim.

Thx 4 your help!

It is applied with the player attack.