Here is how it will work.
TL;DR version
- Can link an account to multiple platforms
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adding cross-save won’t delete the older characters if you have separate accounts on different platforms
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No merging of accounts
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No merging of silver
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No Cross-Play…yet
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whatever you own Game and DLC wise must be purchased on each platform you play the game on. However new light opens a lot of the previous DLC activties for you.
Full Article here