Do I understand correctly that the animal that this is attached to can be anywhere in the arena, and the spell can be moved to an animal in the Beastmaster's zone when the first animal dies?
I have no idea, since I can't find the text or an image of the card on the internet (and I'm not at home so I can't look at the physical card nor load OCTGN). Too bad it isn't in the official
card database yet. *sigh*
To the guys at Arcane Wonders, please, PLEASE, for the love of Asyra, offer a college student a case of beer to update your card database. If you do, it will probably be up-to-date in 2 days: 1 for the student to drink the beer, plus a morning and afternoon to recover from the hangover, then about 2 hours in the early evening to enter the data. There is neither an excuse nor a conceivable reason why this couldn't have been done upon the release of Mage Wars Academy (and Domination). Oh, and while the student is at it, please get her or him to fix the entry errors from the Domination update (e.g. remove "Epic" from the mage type field for Gravikor, Galaxxus, V'tar Suppression, etc, so we can put it in our saved spell books). It's basically an issue of find & replace / copy & paste. Oh, and add Battlegrounds Domination to the "Spellbook Sets" list so we don't have to check off "Ignore card counts" anymore. So... maybe 2.5 hours total on the evening after drinking the beer.
In other words, support your product so it isn't a pain in the butt for your player base to enjoy your flagship game.
[/rant]
*edit* I found this card image on the internet. I can't see it because it's blocked from work, but I was able to see a preview. Yes, looks like you pay 1 mana to move Joined Strength to a target in the Beastmaster's zone, so as long as the creature in the Beastmaster's zone isn't Invisible (and there are currently no ways to give the Invisible trait to an animal creature) it would seem to be possible to move Joined Strength, regardless of where the previous creature was - even outside the Arena (e.g. if it were destroyed by Ghoul Rot or Plagued or Force Crush or something while Exiled or Banished).