Defense formulas how to calculate?

[Minamoto Yoshitsune]

I'm having a hard time solving a recurring problem which is the method by which I will balance the damage of spells with item status. I took 2 tests today.

In the first test I created a skill called poison, where she would give a DPS for 10 seconds, I put 5 as base damage and climbing with 50% of the NPC's AP, in case 5.

 

The damage of the poison ability in the parameters proposed above was around 6/7 DPS with the character having 15 points distributed in Resistencia Magic.

I equipped a shield that gave + 250 RM status bonus and the skill's DPS was 2, that is, 265 only served to block 30% of the DPS.

 

I thought it was a bit out of place because my idea is not to have an exorbitant number distributed in the statuses, the way I thought I could solve this was to redo or modify the physical / magic defense formula, but only we are available the attack formulas, so how to solve that?

[Beefy Kasplant]

Make defense part of the damage formula 

[Minamoto Yoshitsune]

how would you do that?

my idea was that for every 10 points dealt in Defense or Magic Resistance, the character blocks 5 NPC attack damage.

[Beefy Kasplant]

You'll have to make a formula for that. 

 

You can multiply, divide, add and subtract. 

 

You can use the attackers stats and defenders stats

 

You can pick the scaling stat

 

Use all that to make the right formula for your game

[Minamoto Yoshitsune]

math is not my forte, I believe I will be lost in this.