You had obtained a T-60 Power Armour suit from a dead Brotherhood of Steel Knight. After travelling and having fun with it, you suddenly get a call from a Brotherhood operative. You pretend to be the dead Knight and tell the operative that your Squire had died. They then send a replacement Squire almost immediately.

"K-Knight Titus! I-I am your Squire and vow to serve you however possible!" He says, kneeling before you as he carries a large bag of supplies on his back.