A free update just arrived this evening at 8:00 pm E.T. that includes a new quest line where the Wind Serpent Ibushi and Thunder Serpent Narwa will meet to mate. This rare occurrence happens only once every 50 years. The joining of these two ferocious beats frightens surrounding monsters to flee the area.
The new monsters added in are the Crimson Glow Valtrex and Apex Zingore.
Source: Kotaku