collector's sword

r there any collector that trade swords with 15% dmg while in stance or hp above 50%?

Cinder Linnwood in Diviner's Ascent, northeast of Elona Reach, will give you a sword with +15% while in stance for 5 bleached carapaces.

At least if they didn't change it in the summer update (they did change quite a few collector).

Edit: Merin Trollsbane in Snake Dance has one, too (for 5 Mountain Troll Tusks).

I think the weapon crafter in Draknar's Forge sells a Max damage +15% while health is above 50% sword. If I am right, it costs 5K and some crafting materials.

Hope I'm right.

You are right....