do boss souls carry over into ng+?

[shredfactory]

also am i supposed to have doubles of one boss soul, and also what should i do with the boss souls I have more than one of?

[otakon17]

Yes, they carry over if you don't use them. Because it's the Cinders that reset for one, and there are usually 2 things you can use each Soul for(usually a weapon and a spell) sometimes 3.

[Sekiro™: Kebab Burns Twice]

only key items dissapear