The following manga are part of a 6 volume series:
1: Kobomareta Princess
2: Ai o Shiranai Oujo
3: Sheikh ni Kogareru Yoru ni
4: Firenze no Bara
5: Utsukushisugiru Ansatsusha
6: Hangyaku no Prince

These manga should be consolidated under the series title of Ubawareta Oukan. The japanese title is 奪われた王冠

I used 7netshopping as my reference.

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