This is the 9th Guardian Raid in Lost Ark Levanos. He is a tree spirit, and he takes extra damage to fire. I modified my build to include my Detonate Pet and Fire augmented Spear in order to do extra damage to him. This is one of our first kills, shadowplay decided to scramble the actual 1st kill.
In the encounter he starts with extra fortifications. You need to break his extra armor in order to start doing actual damage to him. In order to do this you need to use skills with Destruction attributes, or use battle items that give this property. Our Hawkeye was bringing a battle item that makes the target take additional destruction damage, after that we would throw our Grenades "Battle Items" in order to benefit from the extra break damage to break his armor. After his armor is broken he takes more damage, but he also gains new abilities.
He also spawns an add that you have to kill or else you don't do damage to him. Whenever he does this, he wills till try to attack you. Thus our Bard was using the Scarecrow battle item to taunt the boss in these phases. Sadly we took a break from progression for a month, so we didn't get to kill him before they nerfed him he used to be much harder.