My first time participates in 280 WB (World Bosses) hunt. There are 4 of them; Mirtis, Helgasercle, Marnox, and Rexipher. The one in the pictures is Marnox. Just for clarification, Mirtis and Marnox actually has a level of 265. They’re grouped together with the rest is because there’s either Mirtis xor Helgasercle; or Marnox xor Rexipher; on certain maps when they spawn.
All bosses other than 280 WB has less than 13 million HP. However, 280 WB has more than 250 million HP. Engaging 1 of those sure will consume a lot of time.