This ended up being a very long game
If you don't play the exiled card, it remains exiled
If you've played with the Dryad you know how quickly this can get out of hand
Perhaps the most obvious tribe to try Realmwalker in is Elves, as we see from HamburgerJungs Pioneer list here: Creatures (35) 4 Llanowar Elves 4 Elvish Mystic 2 Dwynen, Gilt-Leaf Daen 4 Dwynen's Elite 4 Gnarlroot Trapper 4 Shaman of the Pack 4 Steel Leaf Champion 4 Elvish Clancaller 1 Realmwalker 4 Elvish Warmaster Lands (19) Spells (6) I would personally want to get Harald, King of Skemfar in here, but its definitely a start
The card with ninjustsu will still be in your hand while resolving the ability and must remain revealed until the ninjutsu ability resolves or is otherwise removed from the stack
Commander Morophon, the Boundless Changeling (This card is every creature type.) As Morophon enters, choose a creature type