excellent entry! 5/5 one of my favs so far
my only criticism is the randomness like others have said, a 1 is always a terrible result and is worthless in combat while a 6 is almost always good no matter the skill, I miss some dice sides with something like "deal 10 damage but you take x damage" so I could use the 1 on these cases. To avoid players rolling dice indefinitely, you could implement some "push your luck" mechanic like a skull side that skips your turn.