And on to the legendaries. In GSC (and HG/SS), supposedly these critters were made as the result of Ho-oh bringing 3 Pokemon who died when the silver shrine burned down.

A popular fan theory is/was that the three that died were the original Eeveelutions (Vaporeon to Suicune, Jolteon to Raikou, and Flareon to Entei). And there was some game info that backs this up- I mean, not only do each of them share a single element type, but they share the same hidden abilities as well! Same relative stat distro (Jolteon and Raikou have high SP Atk and Speed). And to top it all off? The kimono girls in the games who frequent the shrines, often battle using the Eevee line, thus the three dying in fire? Not implausible.