This chart is more a reference. But more or less depending on the way the Link's eye looks can show if it is their "berserk" self fronting or their normal self. Each berserk has their own personalities likes and dislikes. Each of the Berserk's eyes look different to the Link they are from.
B.v's eyes look like a cat and only reflect light from beside the pupils.
B.b's eyes do not reflect light and get extremely dark.
B.r's eyes the most notable difference is that it looks like his pupil has broken.
And B.Gr like b.v gets a catlike pupil, along with his iris shrinking and eyes reflecting very little light.
Shadow does NOT have a berserk self, he is just Shadow.