Runo Ataro

Look:

Info: he loves wolves and chocolate 

Ability: can turn into werewolf

And after the canister he turns into a gigantic wolf Monster

Piece: rook

Sacred gear

Scythe of death

Dragon: Rukaro the black Dragon emperor of despair

human form:

Osiris Orotami
Look

Piece: Bishop

He is a mute and talks through sign

Ability: after the canister incident now turns into a gigantic albino ape

Sacred gear:

Gauntlet of time
(A/N I know it looks like The Infinity Gauntlet so deal with it)
Dragon: Sage the Dragon empress of time

human form: 

hope higashikata (not a joestar family member but it is a jojo referance)
Look:

Piece: knight

Ability: turns into a monstrous crocodile

Sacred gear: sword of Destiny

Dragon: chara the Dragon emperess of Destiny

human form: