I finished watching the Shaman King remake last night, so I'm in the mood to make some Shaman King Rumbles.
Tao Ren and Killua Zoldyck are broadly similar in concept, so they seem like a good place to start.
This will be a standard arena rumble. current Killua vs Tao as of the end of the series (before that last minute timeskip, that is.)
And as a bonus, we'll have a "They sit and talk" scenario as well