"Tamashi no Yoi" you can also say "Youkai no Yoi"
The Japanese word for "water spirit" is "Kappa".
No it is not a Japanese word or name
tamashii
kokoro
there is no such thing as spirit bandit. you can't just make up random phrases and expect them to be translated to japanese. Not True. The Word Bandit is Sanzoku, And the Word Spirit is Ki. So put that together the best way you can.
聖霊 /sei rei/ means 'Holy Spirit' in Japanese.
悪霊 Akuryō
Literally: "Demon" or "Evil Spirit"
tama 霊 "spirit; soul"
'Water spirit' literally translates toæ°´ã®ç²¾ç¥ž (mizu no seishin) in Japanese. There are also creatures called 'kappa' which are considered to be Water Gods.
Yoshi is the indirect Japanese word for "YES", which supports his happy go lucky spirit. In Japan, you can say "yoshi" as yes, but it will be considered bad grammar.
kotta iki is 'frozen spirit' in japanese. hope i helped! :P