Do duel lands count as as both land types? Can a swamp walker swamp walk a dimir land
Only if its {Watery Grave} or {Underground Sea}. Lands must have the land type swamp for swampwalk to work.
RESOLVED
Not just {watery grave} but any shock lands that have the subtype swamp. (i.e. {Blood Crypt}, {Overgrown Tomb}, {Godless Shrine})