▁became ▁known ▁as ▁Los ▁H erman os ▁Sh adow ▁( The ▁Sh adow ▁Brothers ). ▁ ▁In ▁ 1 9 5 2 , ▁the ▁famous ▁wrest ler ▁Santo ▁beat ▁and ▁un mask ed ▁Black ▁Sh adow ▁in ▁the ▁ring , ▁which ▁triggered ▁Blue ' s ▁decision ▁to ▁become ▁a ▁téc nico ▁( a ▁good ▁gu y ) ▁in ▁the ▁ring , ▁and ▁a ▁legend ary ▁fe ud ▁between ▁The ▁Blue ▁Dem on ▁and ▁Santo ▁was ▁started . ▁The ▁story line ▁fe ud ▁between ▁the ▁two ▁cul min ated ▁with ▁Blue ▁Dem on ▁defe ating ▁el ▁Santo ▁in ▁a ▁well - public ized ▁series ▁of ▁matches ▁in ▁ 1 9 5 2 ▁and ▁ 1 9 5 3 . ▁In ▁ 1 9 5 3 , ▁Blue ▁won ▁the ▁N WA ▁World ▁Wel ter weight ▁Championship ▁from ▁Santo , ▁and ▁held ▁it ▁until ▁ 1 9 5 8 . ▁Their ▁rival ry ▁never ▁entirely ▁ab ated ▁in ▁later ▁years ▁( although ▁they ▁co - star red ▁in ▁a ▁number ▁of ▁Mexican ▁horror ▁films ) ▁since ▁Santo ▁always ▁remembered ▁his ▁defeat ▁at ▁the ▁Blue ▁Dem on ' s ▁hands . ▁ ▁During ▁the ▁ 1 9 6 0 s , ▁one ▁of ▁Blue ▁Dem on ' s ▁riv als ▁was ▁el ▁Ray o ▁de ▁J alis co . ▁In ▁ 1 9 8 8 , ▁the ▁year ▁he ▁retired , ▁Blue ▁Dem on ▁defeated ▁J alis co ▁in ▁a ▁mask ▁vs . ▁mask ▁match , ▁taking ▁the ▁mask ▁of ▁another ▁of ▁Mexico ' s ▁wrest