Monsters among lesser gods repulsed (5)
I believe the answer is:
ogres
'monsters' is the definition.
(ogre is a type of monster)
'among lesser gods repulsed' is the wordplay.
'among' says the answer is hidden in the clue.
'repulsed' is a reversal indicator.
'sergo' is hidden in the letters of 'lesser gods'.
'sergo' written backwards gives 'OGRES'.
(Other definitions for ogres that I've seen before include "Terrifying types" , "Giants in fairytales" , "intimidating people" , "Beasts" , "Monstrous giants and man-eaters" .)