Underground Sea Map (War for the Atlas)

Underground Sea Map (War for the Atlas) is a map area and item. The item is a legacy variant of the current .

Boss

Merveil, the Reflection (based on Merveil, the Siren first form).

Version history

Version	Changes
3.6.0	The Atlas of Worlds has been shuffled. Most maps have changed tier and location within the Atlas.
3.5.0	The Atlas of Worlds has been shuffled. Most maps have changed tier and location within the Atlas. Many map bosses have also shifted around. Some have been retired and replaced! (undocumented ) Second stage of the boss, Merveil, the Returned had been added
3.1.0	The entire Atlas has been reworked. Many map names have changed, as have their balance, tier and position on the Atlas. Many maps have also had their boss fights swapped or completely reworked. The rules used to generate monsters in endgame maps have been significantly reworked and rebalanced around the rate at which we expect players to reliably clear out the map. In general, narrow, linear maps will contain fewer total monsters than maps with complex layouts. We will be closely monitoring and adjusting the balance of this change and expect to make further changes and improvements over time.
2.4.0	Most existing maps have been revamped to have more balanced monster composition, layouts, boss fights and rewards. (Not in patch note) The layouts were swapped between Underground River Map and Underground Sea Map. (Not in patch note) The Idol Beyond was removed as map boss. Merveil, the Reflection became the new boss
0.10.0	The following Map areas have been updated so that they're substantially different in layout to before: , , , , , , , , and .
0.9.11	Introduced to the game