making someone or something even stronger, adding a decisive advantage · making a bad situation worse
eş: 鬼に金梃, 鬼に鉄杖, 虎に翼, 弁慶に薙刀, 獅子に鰭, 竜に翼を得たる如し
köken: 鬼 (oni) + に (ni) + 金棒 (kanabō). Literally "[giving] a metal club to a demon". The idiom in general is first cited in a text from 1472 as the longer variant 鬼に金砕棒 (oni ni kana saibō); this shorter form is cited from 1645.
Used other than figuratively or idiomatically: see heittää, löyly, kiuas. · to add fuel to the fire (worsen a conflict)
köken: A reference to being in a sauna. Throwing water on the sauna stove causes it to boil, which increases the humidity and thus the apparent room temperature.