I believe they are obtained through the Dungeon Master Event but I'm a bit sketchy on the details. I think you can obtain them by clearing dungeons as in howicanhelpu's guide.
ok thx now i know were i can get the coins but what about the thing right there that you need to buy the dogi is like a card or something were do you get that
Does any want to have a go at translating the item stats below? Google translate doesn't really give much of a hint as to what these do in game. I had a go at the last one.
유쾌 속성공경 3% 증가
순수 속성방어 3% 상승
용맹 속성공경 3% 증가
마비 지항릭 12% 강화
기이 속성방어 2% 상승
타격 데미지 1 반사
Edit: Translated a bit...
Funny 속성공경 3% 증가
순수 속성방어 3% 상승 - Increase defense against Honest type attacks by 3%
Wild 속성공경 3% 증가
마비 지항릭 12% 강화 - Increase resistance to paralyze by 12%
기이 속성방어 2% 상승 - Increase defense against Strange type attacks by 2%