Fascinating. I thought I knew the origin of "bloody" but before I ran off at the digits, I decided to take a look in the old Oxford Unabridged. As usual, I learned more than I expected. To quote the OED whose explanation seems a bit quaint:

"The origin is not quite certain; but there is good reason to think that it was at first a reference to the habits of the 'bloods' or aristocratic rowdies of the end of the 17th and beginning of the 18th c. The phrase 'bloody drunk' was apparently = 'as drunk as a blood' (cf. 'as drunk as a lord'); thence it was extended to kindred expressions, and at length to others; probably, in later times, its associations with bloodshed and murder (cf. a bloody battle, a bloody butcher) have recommended it to the rough classes as a word that appeals to their imagination. We may compare the prevalent craving for impressive or graphic intensives, seen in the use of jolly, awfully, terribly, devilish, deuced, damned, ripping, rattling, thumping, stunning, thundering, etc. There is no ground for the notion that 'bloody', offensive as from associations it now is to ears polite, contains any profane allusion or has connexion with the oath ''s blood!' "

Sourdough