I blame Thrythlind for the following.
"Fate-chan!"
"...What?"
"Why didn't you tell us that you had a branch of your family that lived on Earth?"
"...I do?"
"Yeah, and she pilots a submarine and commands giant robots."
"...I need to meet her."
*Meanwhile...*
"...Sgt. Sagara..."
"Yes, Captain Testarossa?"
"...I have a feeling that I will be meeting some interesting people soon."
Full Metal Panic crossover for those who don't get it.
Really, Tessa and Fate had the same last name, so... Why not?