Color or picture of the triumph could change when hitting each tier. Perhaps tier specific emblems/backgrounds/name colors could be unlocked when hitting a specific tier. For example

100,000 -> 500,000 -> 1,000,000 kills etc. Tiers could go up to 10 and some new unlocks when reaching said tier.

New name color could be, reach tier 5 on 5 different triumphs. Just another little something that the hardcore players can grind for that can differentiate them a little more from casual players. Hitting a tier 10 in any category could reward AC or something.

Submitted by wsey54