It just occurred to me that there's a 6 month gap between seasons one and two which means Korra had 6 months to talk to her past lives before season 2's finale … I'm going to have fun with it.
Korra sits in meditation at the spiritual center of Air Temple Island. Her eyes closed in concentration, she can feel her spiritual energy spiraling through her chakras…
"It's nice to meet you, Avatar Korra." Avatar Roku sits in front of Korra, in astral projection form. The last fire nation Avatar smirks at the young Water Tribe girl.
"You are very strong and you've done much good for Republic City. You will be a great Avatar."
Korra realizes her mouth is hanging open. The wise old man sitting before her died almost 200 years ago and yet here he was, speaking to her from beyond the grave.
Bowing her head, Korra finally manages to speak.
"Avatar Roku, it's an honor to meet you."
Roku's eyes soften at her formal tone.
"Korra, there is no need for such formalities. You are me and I was you. Tell me, what wisdom can I offer you?"
Korra tenses at the mention of receiving Avatar wisdom. Right now, she didn't need anything. Republic City was on the mend after the Equalist movement, and since unlocking her airbending, she's been diligently studying and putting the work in to master her final element.
"Uh, I don't really need help…" Korra looks away from Roku, as if embarrassed.
She's not sure astral projections can sweat but Roku's confused face makes her feel terrible.
"I'm sorry! I just wanted to...talk to you...about...what it was like for you when you were the Avatar."
Roku offers the young woman a soft smile.
"Avatar Aang only ever summoned his past lives when he needed help…I assumed...what would you like to know, Korra?"
Korra relaxes at the realization that Roku is relieved to have been summoned for somewhat selfish reasons.
"Well, Aang was so intune with his spiritual side he was able to harness the Avatar state as a kid...why do you think it took me years? Did you have trouble getting into the Avatar state?"
Roku offers Korra a gentle smile.
"The Avatar State is a defense mechanism. Aang was able to harness it at the age of 12, not only because he was strong, spiritually...but because his life had been in danger. It is because you were so well protected that the Avatar spirit never needed to be summoned."
Korra slumps back in her meditation stance, stunned. Roku clarifies.
"When Amon took your bending, he used blood bending, blocking the flow of your chakras and your physical tie to the elements, but there is nothing he could have done to stop the Avatar spirit. This is why when he tried to sever your ties to the elements, he ultimately failed."
Korra stares at Roku, absorbing every word. She often wondered why her airbending had been unlocked as soon as she had lost the other elements.
"You never allowed him the opportunity, and thank Raava for that, but it is likely he would not have been able to take the bending of any airbender, for their elemental tie is more than merely the physical."
"So it's a good thing, that I never needed to go into the Avatar state?"
Roku nods, his eyes closing.
"When I was informed that I would be the Avatar, it was my 16th birthday." Roku opens his eyes and Korra sits before him, eagerly listening. "Before then, I had no idea what role I would play in the world." Now it's Roku's turn to slump over, but only slightly, the ever dignified Fire Nation citizen.
"The Avatar has a duty to the world, to protect and maintain balance in the mortal realm. I failed the world and it fell into war for 100 years...Aang was able to learn from my mistakes, like you will learn from his...this is the Avatar cycle…to learn all you can and pass it on."
Roku doesn't say goodbye when his astral projection disappears but Korra knows for now, she is satisfied with the wisdom he's given her.