You could describe to us what they are doing that is so amazing? If you can't do that, then you don't understand the game mechanics well enough to be an accurate judge of player skill.
Alright, blocking efficiency is up to near 99-100% even against lots of 3-5 opponents.
Able to feint extremely quickly (again, quicker than I've seen in any foreign video by 2-3 fold) while maintaining 99-100% blocking efficiency.
Pioneered own movement style for groups, which enables up to 5 opponents to remain suppressed while maintaining blocking/killing efficiency, along with exploiting the increase in speed bonus.
Near 100% Hit Rate on Head, near 0% thud rate from previous speed bonus and head targeting.
An extreme knowledge of stun mechanics, which they abuse quite heavily
When using crossbows, thorn specifically has an extremely high shield bypass rate.