it seems that fiend health absorb is capped at 1000.
This becomes more noticable now because heros have more than 2k health.
Healing is not capped at 1000 which makes fiends worse overtime as hero stats progress.
Example Motega fiend that should absorb 50% healing.
I am not considering it as a bug.
Much earlier there was a bug, where you can do >10K HP minions, and that time Staff capped the minion HP in 1000 as a fix, and it seems it is applied to minions as well.
Well it is a bug, because the special is not in line what it says. it should state it as such then for both minions and fiends in the special (…up to max 1000 health)