Can anyone explain to me how does defense work, cuz i keep taking like 10k per hit or even 1 shotted by most mobs in pipe3. I got 1,4k def, i know its low, but i dont see much difference in damage with lets say 3k def. Can someone inlight me please ?

Uh welcome to 1HKOgiri

Level Disparity is also taken into account. So for example, even if a level 70 person is pumped up to max VIT and other possible means to raise DEF/MDEF, he'd still probably be OHKO'd by monsters with let's say, 20+ levels above him. Hence, the wiki description about DEF/MDEF "having diminishing return."

@ Unnatural: You just gone pulled a Deathy.

To answer OP's question, defense works to such a minimal extent that it's not worth using.

Having more HP is better than def, since it can still save you 1-2 more blows but...

Ultimately, learning the enemy attack patterns, guarding/rolling properly will be your best friend.

You won't be able to do it 100% of the time, but you can do it well enough to at least finish safely within reasonable amount of deaths.

Ok guys thanks alot for your answers !