"To be a younger brother to my son."

"You are here to be a younger brother to my son, Robin," Lady Lysa Arryn informs you.

That takes you by surprise. "What do you mean?"

"I suppose that does deserves some explanation," Lysa remarks, "I suffered a number of stillbirths and miscarriages during my marriage to my late husband. My son, Robin, was the only one among them who lived past birth. I always yearned for more children. By happy coincidence, Robin now yearns for a younger sibling. Alas, his father died before I could give him one. Even so, I have other ways of fulfilling my wish and his."

You quickly realize where she is going with this. "So, you decided to use me for that role?"

"Correct," Lysa Arryn claims, "Let me tell you why I chose you. You were able to make your way through the mountains outside of the Bloody Gate all on your own. Only someone as strong as an Arryn could have managed such an incredible feat. Also, you are quite young, and you do not have the look of a noble. Assuming you knew the risks when you entered the Vale alone, it is unlikely you had any family or friends you were leaving behind. That is what the maester concluded."

"Your maester is right," you reveal, "I came to the Vale looking for work, and I would be content to stay here, as I am alone in the world."

"Not any longer," Lysa counters, giving you a hug, "From now on, you will live with me and Robin as my younger son."

A thought occurs to you. "How old is Robin?"

"Eight," she replies.

You are surprised. "I am almost twice that age."

"I know," Lysa tells you, "But Robin insisted on a younger sibling. I would ask that you indulge his wishes. Whenever he is upset, he gets the shacking fits. Aside from that..."