akuatwu-
I have 1 question well make it 2 whats the last level? and what happens when you win last level?
the EndBoss, EB for short, is in the underwater areas. to get there, you must complete all the quests in otami first (technically you dont, but it will get you more experience if you actually play the game and do all the main quest chains), and then go to the whirpool in gold beach (top left corner) to access it. Imagine Deadman's Pass, except it has 3 different areas inside of it. also, most crews wont take you until you have all or most of your rings at cl 10, so you might want to farm Papa Saw in bass'ken lake before attempting it.
there are a few different terms:
-smob: speed-mobbing the first 2 underwater areas- they're the only ones that have chests that give rewards
-smeb: speed-mobbing EB (endboss)- here you go through the entire thing and defeat the EB
after defeating EB, you are taken to the Bar in Barton Town. if you finish the conversation with everyone who automatically talks to you, you get to choose a cl 10 ring and you get a recipe and a badge. The first 4 times you defeat EB you can get 4 unique recipes (but you only get the cl 10 ring once), and any time after that you get a small amount of gold.
technically, however, there is one more boss after the EB: Kamila in Deadman's Shadow. You need to have all/almost all your rings at cl 10 to be able to join a crew, plus it helps so you can upgrade your rings quicker. To access DMS (deadmans shadow), you must purchase either the Bloodstone Amulet (its equippable, only available on the mp) or Bloodstone Gem (not equippable, in mp and cash shop- cheaper on the mp than amulet), or you can wait till the bar at the top of the forum fills up to gain free access for 3 days until the bar resets again. but you wont make much progress unless you have a bloodstone.