Can someone please tell me what the legendary thing is above my trees?

It happens when a skill reaches 100. Click on that, and the skill will immedately be pushed back down to 15, and you're refunded all points you spent in the tree. The skill can then be re-levelled to 100, I think as many times as you want.

It removes the level cap, basically.

I haven't played in a while didnt know what was up with it. Tyvm for the info!!!

If you do make a skill legendary, try it on a skill you hardly use.

Or one you'll always use but won't hinder much. I plan on revelling one-handed, personally.