I'm worried that if I equip an Elemental/Shadow/Piercing item, then some monsters could do more damage.Help!
Can Elemental/Shadow/Piercing lower your defense?
Some monsters will do more damage, some others will do less, but don't worry this will be more noticeable on T2 and T3.
On Tier 1, everything deals only normal.
Unless you enter a Danger Room after the first half, as the monsters there at the next tier (tier 2). Better say that, just in case... XD
To answer your original question.
No they don't lower your defense. having one type of defense won't make you weaker to another.
different monsters do different types of damage, in the lower tiers they actually always do some normal damage,
so if you trade in normal defense for another type, you may take more damage from some enemies.
Thats why you should have several sets of armors, and change depending on what the next stratum looks like.
u can mix sets and get an all-round defense, for example:
drake & skelly
divine mantle & azure guardian
silvermail & magic cloak
and so on....
@Pathways
There is no way that you can get full defense against everything at once- that's just how the game works. Learn what damage type each enemy deals, and equip your defenses accordingly. If you don't have a proper defense against that enemy, then play very carefully.
Your weaponry has no affect on your defense values.
@Krannx
That will get you killed in T3- though it does work as a starting point when you're T2 F2P.
Otherwise, unless you have full resist against a particular damage type in T3, that resist you have will be near useless, and you'll still go down in 2-3 hits.
It's best to start making extra armors when you can spare the energy.
Some monsters will deal more damage to you due to not having defense against their preferred damage type—using a wolver coat (pierce/normal defense) against devlites (shadow damage), for instance—but this is unavoidable and again is due to lacking something as opposed to having something. If you were referring to specialized damage weapons, then no, weapons do not affect your defense at all.