Complex sentence: Valas wears a shirt of chain mail which is enchanted to give him great agility and balance over this he wears a vest to which are pinned a large number of magical trinkets pilfered from his victims over the years.
Split into simpler sentences: Valas wears a shirt of chain mail which is enchanted to give him great agility and balance. Over this, he wears a vest to which are pinned a large number of magical trinkets pilfered from his victims over the years.