LV Boss Mechanic (help)

[Bozao]

Hello everyone!
Could someone explain the mechanics of the LV tree boss?

We've already gone through it three times, each time in a different way that wasn't repeatable because someone always dies during the cleave.

Thank you.

[Rubius]

Mechanics for all of the Left + Right Wings (which includes Sarthain, the boss you're referencing) are now mentioned here on the Wiki page:
https://wiki.returnofreckoning.com/Lost_Vale

This should have the info you need! Middle Wing mechanics will also be added in the future, but in the meantime player guides will be the best place to find help for that wing.