Also one more things about regeneration the more of if you have the lesser the chance of affliction, (Or at least thats what I've heard) so It might be worth it to forge hydra skin armor aswell.
That is really bad luck:S sorry about it. Don't give up yet though. Try and forge these two items and shoot for const 8
. Pretender is important but not everything(it will still be a big penalty for you)
Edit: I jsut playtested some scenario with diesiesed pretender and for 70 turns now he never got "mute" or "feeble-minded" (he has 20% regen 10 from hydra armor and 10 from ring) (although that depends on how lucky you are and how qucikly you can get the ring)