My thoughts:
- It can't be Loki - if this boy at that age were to do something like that, then - screw IMU - he can solo him low diff.
- It's Harald - the most likely option - although i wouldn't like it much - because, it's a repeat of Oden (a moderately intelligent guy who can accidentally compete with the strongest and has the makings of a ruler).
- My little dream is that maybe this gif doesn't literally mean what it shows - it's just Xebeck choking someone with a haki and that's it.