i have no idea where to find the item for this skill.i have looked everywhere or at least just about but im missing that skill. does anybody know?

White Charm - Gohtza - Backyard - Master Ring User Challenge
Its a Bonus Prize, condition is that you beat the guy's dog first then the soldier.
The dog has +80,000HP though. 

If you get the dog poisened/toxin etc. then it dies in 4 turns though - so use a good Lv3 Toxin Ring or something like that. Then you can just attack the soldier