Air bender for me, and I don't mean to control the rp but the last avatar in the shows was a water bender, this happened around the end of industrial revolution in the 1920's, and with the average of an avatar living to 70 (for those that get killed at like 20-30 and those that live to be 100-120), along with the cycle going water, earth, fire, air, the last official tv avatar being 17, she would have died in 1973, the next avatar would be an earth bender, and would be 41 right now, unless korra lived along time or the earth one died early, then we would have a young earth or fire avatar. The more you know. And yes I did the research, I'm not weird, don't judge me.