Genshin Impact: Challenger: Series IX Achievement Guide

This guide is only for Challenger: Series IX achievements. If you're searching for the hidden achievements in version 4.6, you can find them here: All New Achievements in Version 4.6

All Achievements in Challenger: Series IX

1) Theater Fire Drill

Destroy the Legatus Golem's shield before it can lift its blade and unleash its raging, fiery shockwave. The 'shockwave' here is when the Golem will move to the middle of the arena and stabs its sword to the ground. After that, there will be 3 Pyro shockwaves on the ground before the Golem will lift its blade and unleash the last shockwave.

Destroy the Golem's Geo shield sometime after the 3 shockwaves but before the last shockwave.
Rewards: Primogem x5

2) Unmanifested Sealing Hex

Defeat the Hydro Tulpa after it has become enhanced from absorbing Half-Tulpa(s). Now read this carefully; wait until the boss absorbs the Half-Tulpa before defeating it. Many people would defeat the Half-Tulpa before they can even exist so this time, cut them some slack and let Hydro Tulpa become enhanced first before defeating them.

BUT! Pay attention, you REALLY need to defeat the boss right after it absorbs the little one. If not, you won't get the achievement. Thus, make sure it's HP is low before you let it absorb a Half-Tulpa so you can immediately defeat it afterwards.
Rewards: Primogem x5

3) Three Days and Nights in the Belly of the Great Fish

Escape the belly of the beast without being hit at all by the phantasm(s) within. First of all, you can just choose the lowest difficulty for this challenge because you don't need to claim rewards to get this achievement. Make sure to bring a Fontaine character that can use Arkhe to make this challenge easier. After, hit the Narwhal until you enter the second phase.

Once in the second phase, get far away from the phantasm and avoid any incoming damage. Although I bring a shielder (Baizhu) I never got to use his Ultimate so I don't know if being hit while having a shield still counts towards the achievement. Anyway, hold on until the phantasm turns into a ball, and use Arkhe's power to defeat the ball and instantly get this achievement.
Rewards: Primogem x5

4) "Feng Shui Assassination!"

Within a single challenge, use Elemental Reactions to paralyze the Solitary Suanni while it is gathering Anemo and Hydro adeptal energy respectively. You need to wait until there are 3 Spiritwind Pearls like in the image above.

After that, use Pyro/Hydro/Cryo/Electro on those Spiritwind Pearls to destroy them. Destroying all 3 of them will paralyze Suanni and you will get this achievement. It's recommended to use a bow user because if you get too close to Suanni during this moment, your character will get sucked in by the wind damage around Suanni and can't get near the Spiritwind Pearls.

If you did everything right but still didn't get the achievement, this might be the issue. So I tried with an alt account, and when I destroyed the Spiritwind Pearls without Freezing Suanni when they did the move in the image above, I DID NOT get the achievement. Then I retried again, but this time, I froze Suanni when they did the move above. When the Spiritwind Pearls appear and I destroy it, only then do I get the achievement.
Rewards: Primogem x5

5) If You're Thirsty for Blood...

Unleash 4 Scarlet Nighttides in a single battle against The Knave. You can get Scarlet Nighttides by: (1) Get attacked by the Knave to get the Bond of Life
(2) Clear the Bond of Life by getting healed by a healer or food.
(3) You will get a Scarlet Nighttides. Your next Charged Attack will unleash the Scarlet Nighttide.
Do this 4 times and you will get the achievement.

You can see the Scarlet Nighttide explosion after hitting the Knave with a Charged Attack. I suggest challenging around Level 70-80 The Knave because lower than this will make her too easy to defeat and higher level might defeat you before you can touch her.
Rewards: Primogem x5

6) Brighter Than White

In a single battle against The Knave, avoid being hit by her at all while being affected by a Bond of Life and defeat The Knave. I suggest choosing the lowest difficulty so you can defeat Knave as soon as possible without getting hit by her when you have the Bond of Life (You don't need to claim the rewards to get this achievement). Some things to note;

(1) You need to have a Bond of Life at least once throughout the whole battle
(2) When you have the BoL, avoid getting hit by Knave even one time (if you do, restart)
Tips from yours truly, as I mentioned before, choose the lowest difficulty. Then, get inflicted by BoL in the first phase and make sure to avoid everything. Once you're in the second phase, immediately defeat Knave without waiting for her next attacks. I only got BoL in the first phase and still get the achievement.
It's OKAY if you're attacked by her when you DON'T have any Bond of Life. It's only bad when you're attacked while having BoL.
Rewards: Primogem x10