[Help] How to compute damage for INT

[Blacklizted]

This is from RAN Philippines. The third one has blood lust. Weather is clear in all cases. I would like to know how the novice bamboo blade came up with the highest damage output between the three despite the stats and upgraded weapons of the first two on the left.

The skills used is Sword-INT-197 which has a hp transformation of 3620.

[MentaL]

[Blacklizted]

Or in short, how do you compute damage (on mobs/monsters)?