Since Xiao's release in Genshin Impact, players have been wanting him to have his own dedicated 4-piece Artifact set that synergized better with his kit. Genshin Impact's 2.6 patch introduced The Chasm, and along with it, two new Artifact sets, Echoes of an Offering and Vermillion Hereafter. The latter is a set dedicated to Xiao and has perfect synergy with Xiao and his playstyle.
Xiao was first released in Genshin Impact on his own banner, Invitation to Mundane Life, on February 3, 2021, during Genshin Impact's 1.3 update. Players were thrilled and impressed with Xiao's damage capability and were excited to find out the best Artifacts to use on him. The community decided that the 2-piece Viridescent Venerer set, which gives a 15% Anemo damage bonus, paired with the 2-piece Gladiator set, which gives an 18% bonus Attack, was the best Artifact combination for Xiao to increase his damage.
However, after HoYoverse began to release new Artifact Domains along with new 5-star characters that would include an Artifact set that synergized really well with their kits, players thought Xiao deserved a dedicated set as well, instead of having to mix 2-piece sets together. After Inazuma's release, players started mixing the new set, Shimenawa's Reminiscence (another 2-piece 18% Attack bonus set), with the Gladiator set to further increase Xiao's attack since Xiao has a high base attack and scales well with Attack increases. Still, players wanted Xiao to have his own set since characters like Kokomi and Albedo in Genshin Impact were receiving sets that synergized well with their kits even after their first releases.
Genshin Impact: Why Vermillion Hereafter Is So Good On Xiao
The Vermillion Hereafter Artifact set, along with Echoes of an Offering, was released in Genshin Impact's 2.6 update along with The Chasm, included in a Domain called The Lost Valley. Once players read this Artifact set's 4-piece bonus, they immediately knew who it was for. Vermillion Hereafter's 2-piece set bonus is another 18% Attack bonus set, but its 4-piece bonus is completely unique, and is what completely ties it to Xiao. To summarize, after the equipping character casts their Elemental Burst, they gain 8% Attack, and every time they lose HP, they gain a 10% Attack bonus stack, up to four stacks. So at max stacks, the equipping character will receive a 66% Attack bonus, and stacks clear when the character leaves the field.
Vermillion Hereafter is a perfect pairing with Xiao since Xiao can obtain stacks easily and without any extra effort from the player. When Xiao casts his Elemental Burst, his HP begins to drain, and since his Burst uptime is so long, Xiao can make full use of the stacks for a long time before having to swap off-field. And since Xiao scales so well with Attack, Vermillion Hereafter is Xiao's best Artifact set in Genshin Impact.
HoYoverse's past patches have shown that the developers wish to adjust or buff characters through the releases of new Artifact sets, and that pattern seems like it will persist throughout Genshin Impact's lifespan. Hopefully, HoYoverse can show some love to more characters in the future that need it, like Keqing and Yae Miko. There have been rumors of a new Electro Artifact set releasing in the future, so players can be optimistic that HoYoverse will continue to give great sets to past characters, like Xiao.