Straight 'Ninja' At Meteora In Thessaly, Greece.
Definitely a source of inspiration for some video-game concept art, the monasteries at Meteora were each built by daring monks pulling some over-the-top ninja-stuff, where death was merely seen as a welcome reuniting with 'God'.
Backgrounder: Over seven-centuries old, the monasteries at Meteora were each built by daring monks, willing enough to free-climb to the peaks of each mountain, in search of security, solitude and practice. Traditionally, monastery locations were chosen for their ability to provide monks with (1) enough security to escape from the troubles of war and invasion during the chaotic period that they lived in, and (2) an ideal training ground for practicing the necessary traits required of any ascetic monk: obedience, hard labour and patience. Today, only two monasteries remain active (Great Meteora and Varlaam), with the five others serving as tourist attractions.