Neuter gender.
Well... I don't remember formal grammar rules, so have no idea what declension type it is.
I guess, animate nouns should, as usual, use genitive as accusative plural, but I can't recall any animate -ё noun to prove that. Maybe, there is no one such noun.
The fact that most of the -ё nouns just has no plural forms:
Usual nouns; plural forms exist: остриё - острия, ружьё - ружья, цевьё - цевья, копьё - копья...
Collective nouns, no plural: бабьё, дубьё, зверьё, мужичьё, дурачьё, вороньё, комарьё, бельё, жильё, старьё, сырьё...
Verbal nouns, no plural: мытьё, нытьё, житьё, питьё, шитьё, быльё...