So his grabbing attack goes like this:
-First is high (can crouch)
View attachment 4790153
-Second is low (can jump)
View attachment 4790157
-Third is high again
When the Demihuman boss gives the grabbing attack (lowering the hand) on any side, ran to the other side, stopping beside it's hip is safe from the second grab (or just stay on one side and act depend on it's movements)
If done correctly, you can punish as you crouch dodge 1st and 3rd and poke the 2nd (or do other attack patterns you want)
If he raises both of his hands up:
-Just stand in the middle and jump
For axe throwing demihumans:
-Hug one side of the wall as it can block one of the axes, then just shoot one of it to death