Card Wording

Just curious about card text when referring to master cards that use certain words.

You can choose "Your" vampire..

You can choose "Any" vampire...

You can choose "A" vampire....


Is Any vampire, any methuselahs vampire?

Is A vampire only the acting methuselah or any methuselah?

Not enough information .. or it depends ..


You can choose "Your" vampire..
--> any vampire you control


You can choose "Any" vampire...
You can choose "A" vampire....
--> This is equivalent. But it depends what comes after "a/any vampire". Often you see a "a vampire you control". In that case, of course, it's equivalent to "your vampire". If that's missing, it's any vampire controlled by any player.

Best example is Blood Doll vs. Vessel, two cards providing a similar effect. Blood Doll can only be played on a vampire you control. Vessel on any vampire.

Name: Blood Doll
Cardtype: Master
Master.
Put this card on a vampire you control. During his or her master phase, this vampire's controller may move 1 blood from this vampire to his or her pool or from his or her pool to this vampire.

Name: Vessel
Cardtype: Master
Cost: 1 pool
Master: trifle.
Put this card on a vampire, and you may burn a Blood Doll in play (if any). During this vampire's controller's untap phase, he or she may move 1 blood from this vampire to his or her pool or from his or her pool to this vampire.