Ark of the Knights W, this time the commission is...
Theresa: "Why did we end up in another timeline?"
W: "Don't ask me! In this timeline, your sister, ah, no, your brother killed you."
W (Arknights timeline): "I'm more interested in how the two of you fight after merging into one."
Amiya: "Is there a way to cure Oripathy in your timeline?"
Kal'tsit: "I think I should be the one merging with Theresa."
ff0: "Cut the chatter, Theresa, hurry up and give me some blood!"
Closure: "Are we talking microtransactions?"
Actually, this is a story about W, a Kamen Rider from another timeline, showing up in the Arknights timeline.
And of course, merging into one is the main way they transform.