A short while before Tsunade made the bet.
A soul that floated through the void was being tugged towards the underworld when it was suddenly snatched off its path and brought before a goddess. "Hello, little one. Welcome to the room of rebirth," the goddess said with a smile.
"Why am I here? I just wanted to be done," the soul lamented as he looked up at the goddess.
"Where would you like to be reincarnated to?" the goddess throws out following the usual dialogue for those who have a "choice" completely ignoring the souls question.
"I'd honestly rather not be reborn, reincarnated, or transmigrated at all," the man replied.
"Unfortunately, you don't have that option. You either get reincarnated randomly or choose where to go," the goddess said curtly as the back of her neck started to sweat. She had taken a risk to pull this particular soul off of the path and couldn't let it go back or she'd not only be in trouble but also lose the interesting soul itself.
"Okay, can you send me to my favorite anime's world, if that's doable?" the man requested in resignation.
"I can do that. You will be sent to the world of Naruto then" the goddess stated as she looked at the soul of the man she'd just pulled from the usual path of rebirth.
"Sounds good to me," responded the man as he just kind of floated there. "I mean, if I have to go, at least it's somewhere I like; since it's either that or somewhere completely random."
"You're not gonna ask if you get wishes or anything like that?" The goddess queried with an amused sparkle in her eye.
The man had been silently waiting to be sent on his way after confirming his location. "Not really, I kind of figured I'd get what I get. At this point, at least I get to live where I want to."
"I'll let you make some 'suggestions' if you make a deal with me -- no wishes, though. That would be boring," the goddess said with a thoughtful expression. Internally, she was begging him to accept since it would be more fun for her that way. "Before you ask, the deal is to accept a small challenge that won't threaten your life." 'Directly' she thought at the end of the statement.
"Fine, I don't want to be super strong or overpowered anyways I'd rather just enjoy life."
"Good, so any suggestions?" She asks while trying to keep a grin off her face.
"As for suggestions…" he thought for a minute. "It'd be nice to be the child of Tsunade in Naruto. Having a tailed beast as a lifelong partner is good too, even if there's that risk. Also, I'd rather not remember anything at all as to avoid knowing the plot line. I feel like it'd be a complete drag constantly thinking about what could or would happen based on my actions. Could you get rid of any needless memories altogether?"
"Ara Ara, unfortunately some things you will need to remember. Otherwise, the deal would be boring." she says to him.
"Fair enough. Just erase the extraneous things then?"
"Okay, done. Now off with you," she says lightly, whisking him away. Kukuku~ now to set up some "surprises" for my little Hime to make this fun. The goddess mischievously laughs.