How to Get Agnidus Agate
You can get Agnidus Agates by defeating the weekly Bosses, but the better way is to grind the Pyro Regisvine. You can also convert other kinds of these Ascension materials to the right ones, so if you have a surplus you can transmute them with Dust of Azoth.
When fighting the Pyro Regisvine, you can easily take down its shield with even weak Hydro type attacks. Every player should have a Barbara, so you can quickly take down its shields at the start of the fight. Make sure Barbara has Thrilling Tales of Dragon Slayers as her Catalyst so the DPS character you switch into can do more damage.
How to Get Whopperflower Nectar, Shimmering Nectar, Energy Nectar
Nectar is a drop from Whopperflowers, and I find that a lot of character and weapons need it. You’ll want to take down Whopperflowers whenever you see them. They can be tracked with the Adventurer’s Handbook and respawn every day. There are two Whopperflowers right before the entrance to the Pyro Regisvine’s cave.
How to Get Teachings of Diligence, Guide to Diligence, Philosophies of Diligence
The Talent books you need for Hu Tao can be obtained at Taishan Mansion on Tuesdays, Fridays and Sundays. As a Domain, you need 20 Original Resin or a Condensed Resin to claim its rewards. For the first three levels of this Doman challenge, you’ll be fighting Pyro Slimes that explode and Pyro Abyss Mages. You’ll have six minutes to take out all the enemies.
For the hardest challenge, you fight against two Blazing Axe Mitachurls and two Fatui Pyro Agents. The Agent will be able to explode like the Slimes in earlier difficulties. You have eight minutes to defeat them all.
This challenge is made substantially easier in co-op, as your damage output will be at least doubled. Focus on making elemental reactions on the same enemy to get them out of the way before teaming up on the next one. If you have a Ganyu or Amber on your team, their Elemental Skills can draw the Fatui Agents’ aggro. The decoys are most useful for sponging up the Agent’s deadly dash attacks that can kill you if you’re not careful.
How to Get Juvenile Jade
Juvenile Jade is the World Boss drop you need to Ascend Hu Tao. Unlike previous Pyro characters, you won’t need the Everflame Seed from the Pyro Regisvine. Instead, you have to take on the Primo Geovishap at Tianqiu Valley. You’ll need 40 Original Resin to redeem the rewards from defeating it, but you’ll always get at least some Juvenile Jade for doing so. It also can drop the elemental gems like the Agnidus Agate you need for Hu Tao, but the kinds it drops are random. Convert the ones you don’t need into Agnidus Agate.
When fighting the Primo Geovishap, you can use Shields to bounce back its elemental attacks. Most of its moves require it to be up close to you, so using ranged characters will help. I recommend playing this Boss in co-op mode, with one player drawing its attention while another player takes shots at it from a safe distance.
How to Get Silk Flower
Silk Flower is a Liyue specialty that is one of the easier materials to find. You can find Silk Flower in two locations: Yujing Terrace in Liyue Harbor and by the entrance to Wangshu Inn at the base of the tree. They’re easy to find: just look for the bright red bushes. They take two days to respawn, so be sure you’re hitting up the bushes to get enough Silk Flower. They’re good to get even if you already have enough for Hu Tao since the other character that needs them, Xingqiu, is one of the game’s best support units (and plays really well with Hu Tao).
How to get Shard of Foul Legacy
This item is one of the three special drops by defeating Childe during the Lv 70 weekly Boss Fight at the Golden House. Childe also drops any variety of elemental gemstones like the Primo Geovishap, so you can convert the ones you don’t need. You need 60 Original Resin to redeem the rewards, and you can only do so once each week.
I recommend having at least one each of a healer and shield generator. Luckily, Noel and Barbara were made accessible for free-to-play players. Childe hits really hard, and is even more deadly in this challenge fight than in his story battle. He can often one-shot your characters, so use shields to stop the narwhal he summons or the Riptide bolts he strikes with in his second and third phases.