@DarthParallax

Valor, Wonder, Filth, Anger and Brawn were a separate 'cycle' of incarnations to genesis and glory, albeit in the same set. But the former were all 4 cost, uncommon 2/2's (except brawn with, understandably, +1/+1) with a 'color related' effect and gave that effect to your army when they were in the graveyard and you controlled a 'same color' land (though I do agree Filth could've been way better with fear), whereas as the latter two are 5 CMC rares with a {2} + own color ability that could only be activated when theyw ere in the graveyard

Later, in Lorwyn, we got the 'elemental incarnations' cycle who always were shuffled back into the library when they went to the graveyard and provided an effect while on the battlefield