Genshin Impact 5.0 and the release of the new Natlan region are due later today, August 27, for much of the world. New Hydro 5-star Mualani will kick off the regional expansion with her debut banner, which is scheduled to drop at approximately 8pm PT / 11pm ET / 4am BT depending on maintenance downtime.
Developer HoYoverse warns that "in version 5.0, to optimize the update installation speed after pre-downloading on hard disk drives, the required space for PC pre-download is relatively large, and is approximately 26 - 38 GB (with the resource package occupying 16 - 23 GB)." You can already pre-install today's hefty download to prepare for the patch, though you'll still have to jump through a few hoops on startup.
Mualani will debut alongside a rerun banner for popular Anemo user Kazuha. The 4-star characters on their banner are Bennet, Xinyan, and new Geo user Kachina (who will also be given out for free in Natlan). The second half of update 5.0 will feature new Dendro 5-star Kinich and Electro Archon Raiden Shogun. Their 4-star lineup hasn't been announced.
Like many Natlan characters, Mualani comes with a unique movement ability. She can surf around on a shark-like creature, and certain environmental features in Natlan let her move especially quickly over short distances. In combat, she's positioned as a hard-hitting on-field Vaporize DPS who wants Pyro teammates to set up her big, infrequent hits. Surf through enemies to mark them, and once you have at least three marks, fire off a volley of shark bites and missiles.
Kachina seems to be a more typical off-field support DPS, and somewhat weak at that, but she also comes with a special movement function. She can ride her deployable drill like a giant top and even skate up cliffsides. Kinich, meanwhile, has a Dendro grappling hook capable of huge leaps. If you're not interested in these characters, you'll find dinosaur-like critters in Natlan that offer similar exploration bonuses.
New Genshin Impact character Xilonen was just announced for update 5.1, and the open-world RPG's next Natlan hero and latest Geo 5-star is also another cat-girl.