Arknights recently made a statement on copyright infringement.
[Statement on Copyright Infringement of Roaring Flare Animated Video]
— Arknights_EN (@ArknightsEN) January 16, 2023
As the publisher of Arknights overseas and cooperating company with Hypergryph, Yostar will actively work together with Hypergryph to maintain the relevant rights and interests.#Arknights #Yostar pic.twitter.com/6OKsGNSLPv
Hypergryph, the developer of Arknights, also released a statement today saying that it has never had any partnership with Oldeus.
Meanwhile, here is a statement from one of the Oldeus members:
Oldeus' unofficial response
Hypergryph is currently considering possible legal recourses.
Source: Twitter