During the first two months the release of new content for the PC version of Monster Hunter: World was a little bit slow, but thankfully it appears that Capcom has now decided to bring in new monsters a lot more swiftly. Just recently we have received the golden-scaled Kulve Taroth as a challenging boss to fight, and now we have two additional monsters to square off against: Teostra's mate Lunastra, as well as the immensely dangerous Arch-tempered Kirin.
If you're planning to go after Lunastra, you'll be able to use her materials in order to craft new weapons, a unique armor set, as well as a new Palico armor. On the other hand, if hunting down Kirin is more up your alley, you will be able to use its parts to create a brand new set of armor, as well as the cosmetic "Blossom Layered Armor". And in order to make all of this just slightly easier, you are now also able to acquire a new specialized tool - the Temporal Mantle that protects you from powerful attacks by automatically dodging.
In order to face off against Lunastra you will first need to 'complete the game' and acquire Hunter Rank 16, after which you'll be able to talk to the Huntsman in order to start the quest. As for Kirin, given how insanely powerful the Arch-tempered versions of monsters are, it shouldn't come as much of a surprise to hear that you will need Hunter Rank 50 in order to even attempt the quest.
You can learn more about these additions, as well as check out what else the update has brought in, by heading over to Steam. Happy hunting!