 The tengu 's unpleasant image continued to erode in the 17th century . Some stories now presented them as much less malicious , protecting and blessing Buddhist institutions rather than menacing them or setting them on fire . According to a legend in the 18th @-@ century Kaidan Toshiotoko ( 怪談登志男 ) , a tengu took the form of a yamabushi and faithfully served the abbot of a Zen monastery until the man guessed his attendant 's true form . The tengu 's wings and huge nose then reappeared . The tengu requested a piece of wisdom from his master and left , but he continued , unseen , to provide the monastery with miraculous aid . 
