Yes, having Warmonger definitely increase your enmity hold over, if in GLA, War Drum + Warmonger + cadence + Circle Slash II to hold on to multiple enemies. change Circle Slash to Riot Blade for singular target.

Heavy Slash and Heavy Stabs give enmity too.

p/s:
Defender (Level 10 Gladiator) [Defender II if possible]

is Level 10 Marauder.