Question About Percent Health Magic Damage

Because magic resist makes it do less damage

Let's say your enemy's pizza(Hp) was split into four slices (Hp), my mouth (skill damage =25%) can only handle 1 slice (25%) every time I spam my mouth(Skill). I hate olives(armor) so I bite around it. All the slice have 50% olives(armor on it). So every time I try to eat(damage) 1 slice(25% per hit). I end up only eating(damaging) only half of a mouthful of pizza(12.5%) because 50% of the olives(armor) is still on it. But since there are too many olives(armor) and I couldn't eat(damage) the parts that the olives(armor) were on. So I got to take(Buy) my hands(magic pen or lethality) and take off the olives(armor). By taking(buying) about 6 (lethality items +18 on 1 lethality weapon) fingers to remove all the olives(Armor) off the pizza(hp), I can now take 1 slice(25%) without worrying about any olives(armor). Now since that 6 fingers took off all those olives, now you can munch(do true damage) on that part. Kinda like that if you know...