Thief Profession: My Profession Is a Bit Weak

[Navigation adventure + multiple heroines + slow heat + group portrait + freedom] Pirates attacked a merchant ship and killed everyone for an item, but the item could not be found. All the merchant ships were supposed to be dead, but someone miraculously survived. That person took that thing and drifted to an island... Also involved in the crisis... In the end, the boy raised the banner of rebellion and pulled everyone into madness.