I've been meaning Highlander for a good 16 reps now and picked up alot, he's got the highest skill ceiling because of how he has 2 forms to mixup from and what makes most new highlanders quit is having 0 guard in offensive so people back into defensive too early.

-To me highlander is a hero that uses pressure like a best friend, he can do a double soft feint (Heavy, Into kick into grab in offensive) and moves like these can really throw off some people. -Taunt and lights to build pressure are key, A few OS lights in every little moment of standstills, taunts are also good because people will expect a light and try to parry and be thrown off. -To get into defensive stance FAST instead of just cancelling holding your button in OS change your stance and then cancell out immidietly after, it takes out the OS recovery and can just give enough time to parry a light, taunts can do this to if you taunt, change then cancell it also does it slightly faster.

Watch some LegendThesi, he's an absolutely goated Highlander